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Version 1.0

THE LIGHT SIMULATOR

Version 1.0

THE LIGHT SIMULATOR

Maxwell Render – User’s Guide

CONTENTS _______________________________________________________________ LICENSE AGREEMENT 3 WHAT IS MAXWELL 4 MAXWELL FEATURES 5 MAXWELL SOFTWARE PACKAGE 8 INSTALLATION AND LICENSING 8 Windows 8 Linux 8 MacOSX 8 USAGE 9 MAXWELL STUDIO (MXST) 10 INTRODUCTION 10 PANELS 12 IMPORTING GEOMETRY 13 USING PRESET GEOMETRY 13 USING GRAPHICAL VIEWPORTS 13 Navigation 13 2D/3D Viewports 14 Selection 15 Move/Rotate/Scale 16 Advanced editing 17 Display modes 18 Display preferences 19 OBJECTS 20 Groups 20 MATERIALS: INTRODUCTION 23 MATERIAL BROWSER 24 MATERIALS: NEW MATERIALS 25 Create a new material 25 Assign material to single objects 25 Assign material to selected objects 26 Assign material to groups of objects 26 Assign material to faces 26 Assign material to triangle groups 26 MATERIALS: EDITING 27 Material layers 28 Adding/ removing layers 28 Basic layer properties 29 BSDF properties 29 Clipmaps using transmittance mapping 34

BSDF examples 34 Coating properties 35 Subsurface properties 36 Emitter properties 36

Next Limit Technologies 1


Emitting materials 39 Blending layers 39 Material preview 39

CAMERAS 41 Creating a camera 41 Camera focus 43 SKY OPTIONS 45 RENDERING 48 MAPS AND TEXTURES 53 Creating a map projector 53 Projectors parameters 54 Applying textures 55 Texture picker 56 Color picker 57 MAXWELL MATERIAL EDITOR STANDALONE (MXED) 58 MAXWELL RENDER ENGINE (MXCL) 59 MAXWELL VIEWER 62 Menu functions 62 Toolbar 62 Console/Scene Data Panel 63 Render options panel 63 Preview / MXI panel 65 Multilight panel 67 Network panel 69 NETWORK RENDERING 69 TUTORIALS 72 Tutorial 1: The plane 72 Tutorial 2: Basic Studio Environment 75 Tutorial 3: How to make plastic-look materials 79 Tutorial 4: AGS (Architectural Glass Solution) Materials 83 KEYBOARD SHORTCUTS 86 File 86 Navigation 86 Selection 86 Edit 86 Window 87 Display 87 Render 87 IOR FILES 88 ACKNOWLEDGMENTS 89



LICENSE AGREEMENT _______________________________________________________________ Maxwell Render™ (Copyright/License/Warranty) This software and documentation is Copyright 2006, NEXT LIMIT S.L. referred below as author. MAXWELL LICENSE AGREEMENT Full ownership of this software, and all rights pertaining to the for-profit distribution of this software, are retained by NEXT LIMIT S.L. This software can not be bundled with any commercial package without express written permission from the authors. This license is not a sale of the software or any copy. You may not disassemble, decompose, reverse engineer, or alter the software or any of the files contained in the software package. THE SOFTWARE IS PROVIDED 'AS-IS' AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.



WHAT IS MAXWELL _______________________________________________________________ Maxwell is a new render engine based on the physics of real light. Its algorithms and equations reproduce the behavior of light in a very accurate way. All of the elements in Maxwell, such as light emitters, material shaders, cameras etc., are entirely based on physically accurate models. Maxwell’s method of calculation always converges to the correct solution without introducing artifacts due to the fact that it is an unbiased render. Unbiased means that no tricks or interpolations are used to calculate the lighting solution in every pixel. It can fully capture all light interactions between all elements in a scene. All lighting calculations are performed using spectral information and high dynamic range data. Maxwell operates as a stand-alone command line application that targets many different environments like high-end rendering, architectural, production, and scientific. Maxwell has been built for Windows, Linux and MacOSX platforms. This version includes plugin connections to 3dsMax, Viz, Maya, Lightwave, Rhino, Solidworks, ArchiCAD, Cinema 4D, formZ and Sketchup. Additionally, other file formats are supported such as OBJ, STL, LWO, NFF, XC2, DXF, 3DS, XML AND FBX. Maxwell includes features such as material editor, material browser, texture mapping, light and camera editors, sky options, etc. (all based in physically accurate models). The 1.0 version provides both GUI and command line functionality.



MAXWELL FEATURES _______________________________________________________________ Based On Real Physics One of the principal characteristics of Maxwell is that the rendering technology is strictly based upon the real governing physical equations of light transport. Maxwell is capable of producing incredibly realistic illumination results without having to resort to the illumination tricks used by other render engines. Consequently the results produced by Maxwell are highly accurate renditions of the real world. Spectral Calculations for Light and Object Properties It is very common, even standard nowadays, that most render engines perform calculations in a specific color space (typically RGB). However, this is physically incorrect and therefore Maxwell avoids this approach and considers real world behavior instead. In harmony with reality, Maxwell considers light as an electromagnetic wave defined by a frequency spectrum. Maxwell considers a spectrum which ranges from the Infrared to the Ultraviolet. Once Maxwell has completed the rendering procedure, each pixel in the output image contains different amounts of spectral energy. This energy was sourced from the lights in the scene and arrives at the conceptual film/sensor of the virtual camera or at the retina of the viewer. Maxwell stores this information in a new format called MXI (high dynamic range format). The pixel color which is generally the final desired result is an interpretation and sensation of the different frequencies which arrive at the film/sensor or the retina. Maxwell simulates this process and ultimately transforms the spectral measures into known color formats such as XYZ, RGB etc. Full Global Illumination Maxwell calculates all possible interactions between light and the objects within a scene. These interactions range from the usual indirect diffuse illumination now handled by most render engines to much more complex lighting scenarios such as indirect glossy caustics caused by volumetric objects which are participating media. The global illumination interacts with surfaces and also layers beneath the surface to produce translucency and subsurface scattering effects. It also interacts with the space between objects when a participating medium exists (causing absorption and scattering) and all combinations of this behavior are possible. Materials Based On Real Optical Properties Maxwell materials are modeled in a physically correct manner. They are defined from their BSDF curves (Bidirectional Scattering Distribution Function) adding the ability to superpose different layers of physical materials in the same object like other BSDF or SSS (sub surface scattering) effects. Thin coatings are also available for very subtle and realistic effects. The possibility to use direct IOR data files measured in laboratory allows rendering real life materials easily. Unbiased Rendering Maxwell is an unbiased render. Unbiased means that, with sufficient render time, the rendered solution will always converge to the correct result without the introduction of artifacts. Other rendering engines based upon widely known techniques such as photon mapping, radiosity, light maps, irradiance maps or other interpolation methods always produce biased renders. Consequently, they cannot guarantee convergence to the correct solution no matter how much time is expended on the rendering process. Multiprocessor Maxwell can exploit all of the processors available on your system and can make the work simultaneously on the same render to provide faster renders. For example, on a multiprocessing platform with 8 processors a user can expect up to an eightfold increase in render performance/speed.



Real 3D Motion Blur Maxwell doesn’t produce motion blur as a post-process or using various tricks. Instead Maxwell considers the moving objects to have random positions along their trajectories during the camera shutter speed time. This creates a natural and realistic motion blur. It also can compute the full global illumination effects for the moving object i.e. a moving glass object producing caustics will produce blurred caustics and even volumetric blurred caustics if a participating medium exists. Simulation of Realistic and Complex Caustics Any scene containing complex caustics can be simulated. These include reflection and refraction caustics produced by indirect or direct lighting, caustics produced by dielectric materials, plastics or glossy metals. No restrictions at all are imposed on the nature or the number of caustics in a scene. Realistic Camera Model Cameras in Maxwell operate completely differently to those in other render engines. Traditionally, most render engines use a pinhole camera. This type of camera simulates a tiny hole that allows light rays coming from the scene to reach the viewing surface. Maxwell simulates a real camera with the associated lens set, diaphragm aperture, diaphragm blades etc. By using this type of camera model Maxwell can automatically simulate depth of field, motion blur effects, image distortion and color dispersion due to the lens set. All other render engines currently on the market use post-render filters or special tricks to create these effects. Object Light Emitters as Light Sources Maxwell is a physically-based render and it only uses objects whose area is greater than zero as emitters emulating what happens in the real world. This approach produces a higher degree of realism in comparison to traditional render engines outputting smoother shadows and increasing the overall quality. Another important characteristic of the Maxwell render engine is the number of lights that can be placed in the same scene. Most other render engines cannot handle a large number of area lights without incurring a significant performance loss. Light sources in Maxwell are defined by spectral characteristics. Thus a light source can possess a lot of information about the intensity of emission at any of the possible wavelengths. The objects emitting light inside Maxwell can be made of any material the user chooses, this way if the light is “on” only incandescence can be seen but if the object is “switched off” the base material (metal, crystal… any material) will be revealed. Physical Sky Maxwell incorporates a physically-based sky simulator: the user simply specifies the geographical location and the time of day for a scene and Maxwell will automatically handle the rest. This physically-based sky model will also include an extension to simulate special lighting conditions such as moon light or various atmospheric phenomena. Glare system Diffraction happens when light goes through small holes, and behaves like waves. It is very important in optics, as it explains why a perfect telescope ( or microscope ) that can take a photo of a star and render it as a single dot instead of some circles or streaks does not exist. Maxwell incorporates a system where the user can define a pattern to simulate the shape of the diaphragm that will model the pattern of light reaching the film having the possibility to be blocked by obstacles such as dust or drops or eyelashes which causes more realistic diffraction



Clipmaps Clipmaps are a much extended feature when producing digital imagery; it allows cutting a polygon in a specific shape, optimizing complexity of the geometry needed. Maxwell Render makes use of the materials properties to simulate clipmaps for rendering things like plants, leaves and so on. Emixer Emixer is an advanced tool for editing lighting. It allows changing the intensity of individual lights during and after the rendering process. These changes affect all global illumination and lighting aspects of the scene. Emixer is also a real compositor that can make a video animating lighting from a single render. Compatibility Maxwell is a standalone application compatible with Windows, Mac OSX and Linux in 32 bit flavors. There are also a bunch of plugins connecting Maxwell to the most popular 3D applications including 3dsmax, Maya, Cinema4D, Lightwave, Houdini, Rhino, Solidworks, SketchUp, Form-Z, Archicad, etc. although an alternative workflow is possible using Maxwell Studio, a full featured 3D application that includes: light editors, material editors, render management, distributed rendering, MXI viewer, physical sky editor, tone mapping process, etc.



MAXWELL SOFTWARE PACKAGE _______________________________________________________________ Maxwell Render includes three different applications: the render engine (MXCL.EXE), the standalone graphical application, “Maxwell Studio” (MXST.EXE) and the standalone material editor with browser (MXED.EXE) for the plugins. The software distribution also provides a set of plugins for the supported 3D/CAD applications (available in the download page). Check the specific documentation included for every 3D plugin available. The plugin takes care of collecting the scene information, applying Maxwell materials to objects and sending the full scene to Maxwell for rendering. INSTALLATION AND LICENSING [Windows] Run the installation file (maxwell.exe) and follow the installation procedure. The Maxwell executable files will be added to the system path. A user environment variable named MAXWELL_ROOT pointing to the installation folder will be added. If this variable doesn’t exist or is not created properly, the application will fail. License the software by adding the “license.dat” file sent by Next Limit to Maxwell using the menu option “Help > New License”. Alternatively you can copy the “license.dat” file into the Maxwell folder. [Linux] Install the RPM package.

rpm –ivh maxwell-1.2.2-1.rpm

Create a user environment variable named MAXWELL_ROOT that points to the Maxwell installation folder. Depending on your shell, the procedure may differ slightly. For example, in Bash shell use:

export MAXWELL_ROOT=”/usr/NextLimit/Maxwell” export PATH=”/usr/NextLimit/Maxwell/bin:$PATH”

In csh shell:

setenv MAXWELL_ROOT ”/usr/NextLimit/Maxwell” setenv PATH ”/usr/NextLimit/Maxwell/bin:$PATH”

License the software by adding the “license.dat” file sent by Next Limit to Maxwell using the menu option “Help > New License”. Alternatively you can copy the “license.dat” file into the Maxwell folder. [MacOSX] Unstuff the installation package and drag & drop the contents into the Applications folder. License Maxwell Studio by adding the “license.dat” file sent by Next Limit using the menu option “Help > New License”. License MXCL by copying the supplied “license.dat” file inside Maxwell/Contents/MacOS) (Ctrl-click on maxwell, Show Package Contents, navigate to /Contents/MacOS).



USAGE Maxwell Render contains three main executable files: MXCL (Maxwell Render) This is the standalone render engine. It can read and render MXS (Maxwell Scene) files. MXST (Maxwell Studio) A complete GUI application to create and render Maxwell scenes. MXED (Maxwell Material Editor) Standalone Material Editor with Material Browser for plugins. It is also used for creating materials libraries. Maxwell Render provides two alternative workflows. There is no difference between each of them, as they are both very powerful. Just keep on reading and find out which suits your pipeline best: A) FROM THE 3D APPLICATION USING THE PLUGINS By using the available Maxwell plugins for each 3D application you can assign Maxwell materials from the advanced material editor and export the scene to MXCL and render it or export it to Maxwell Studio for advanced editing. MXCL can also be run from the command line by providing a valid MXS (Maxwell Scene) file. It is recommended to check the documentation of the plugins for specific usage. The most basic (command line) method to use MXCL is by providing a MXS scene in the form: mxcl -mxs:scene.mxs A path to the scene can be added without problems: mxcl -mxs:c:\scenes\scene.mxs By doing this, MXCL will start in no-gui mode, so no render display is available. MXCL can also display a simple interface (Maxwell Viewer) to visualize the render in progress. To open MXCL with interface the -d option is required (you can also click the MXCL shortcut in Windows). mxcl -mxs:scene.mxs -d B) FROM MAXWELL STUDIO Maxwell Studio does not require any plugin since it is an independent application. With Maxwell Studio you can import objects in different formats, apply materials, lights and textures, and render the scene. This kind of workflow is mostly recommended for people working with 3D applications that do not have an available plugin to directly connect their scenes to MXCL.



MAXWELL STUDIO (MXST) _______________________________________________________________ INTRODUCTION Maxwell Studio is a full, standalone application to render scenes and objects imported from other 3D applications. Maxwell Studio provides the following functionality: • Import object files • Set attributes of objects (position, rotation, scale, pivot, smoothing, normals, etc) • Apply textures using UV projectors • Apply physical materials and lights • Visualize the 3D scene in graphical viewports • Create multiple cameras • Set sky options • Fully customizable layout • Libraries of preset scenes, materials and layouts

Maxwell Studio’s layout is fully customizable. Each window can display any of the available built-in panels by clicking in the upper left icon and choosing the appropriate panel.

Switch panel



Panels can be moved from their place to another by a simple drag and drop from their title bar. This makes it very fast and easy to configure a layout. Also, the panels can be undocked from the main layout by clicking the icon in the title bar. Once a panel is undocked, it can be docked by drag and drop on its title bar.

There is a possibility to create new floating windows by using the main menu option “Window”. Panels can also be removed by clicking in the title bar. The layout always reconfigures automatically, expanding or stretching the rest of panels. It is recommended to get used to these panel features as soon as possible, opening and closing panels and configuring different layouts. You can use the menu command “Layout” to restore to the default layout (defaultlayout.xflay) or load and save new layouts. Saving any layout as “defaultlayout.xflay” will make it the default layout when Studio is launched. A set of layouts is available under the layout folder on the installation. These layouts are focused on different tasks like mapping, rendering or editing. You can swap between them when working with the “Load Layout” command under the “Layout” menu.

Different layout examples Panels can split vertically and horizontally, allowing new panels to be added to the layout. That is the usual way to build a new layout, by splitting the existing panels and adding new ones. The split quad option creates 4 new panels and replaces the original, as shown in the images.



Split panel

Split Quad in the graphic viewport

PANELS Maxwell Studio provides different panels for different functions. The panels can be accessed by switching an existing panel or using the menu command “Window” to open a floating panel. • 3D viewport perspective or camera viewport (ALT + 1) • 2D viewport orthogonal viewport (ALT + 2) • Material list list of materials available in the scene • Material editor advanced edition of the selected material (ALT + 3) • Material browser gallery of materials • Projections list list of UV projectors for object texturing • Projections param table parameters of the selected UV projector • Sky options set sky options • Render options general rendering options (ALT + 0) • Object list list of imported objects • Object param table parameters of the selected objects • Triangle group list list of triangle groups • Triangle group param table parameters of the selected triangle group • Camera list list of created cameras (ALT + 8) • Camera param parameters of the selected camera (ALT + 7) • Console console messages • Timeline Timeline in frames Shortcut: ALT + number = switch the current panel to a different panel depending on number. Most of the panels have numerical properties. These properties can be edited by typing new numbers or, alternatively, using the middle button of the mouse and dragging up and down to scroll the number.



When several objects are selected, some parameters will show an orange color. This color means that those parameters are “multi-evaluated” and contain different values for each object. The colored value shows the values of the last object selected. If a multi-evaluated parameter is changed, the variation will be added as an offset to all the objects in the selection. To check this, selected several objects and change their position.

IMPORTING GEOMETRY

Maxwell Studio supports several scene and file formats. In following versions, new formats will be added. Currently, the file formats supported are: OBJ, STL, LWO, DXF, NFF, 3DS, FBX, XML (AllPlan 2005). Some of these formats only store one single object while others support any number of objects. Maxwell requires these formats to provide 3D polygonal data as triangles. Other geometrical entities are not supported. Maxwell Studio can load and save MXS scenes (Maxwell scene file format). Maxwell can import MXS scenes previously exported through the plugins from the 3D applications. In order to import objects in Maxwell Studio, use the menu command “File Open scene” or “File Import object to Scene”. Alternatively you can right click in a graphical viewport to access a list of actions, and choose “ Import object to scene”. When Maxwell Studio saves the scene, everything is packed in a MXS file, therefore the original object files are not needed anymore. When Maxwell tries to import an object that has a name conflict with other object in the scene, Studio displays a dialog to choose amongst different replacement options. This is a very interesting feature, as the geometry of the objects can be changed without removing all the material properties, just replacing geometry. USING PRESET GEOMETRY LIBRARIES It is also possible to load any of the preset scenes and objects available with the installation by clicking on “File -> Load environment” and “File -> Load object from library”. By loading any of the environments the user will have a studio-like environment to render their own objects. Please note the environments are set to match a certain scale, so have this in mind to choose one or another. USING GRAPHICAL VIEWPORTS The graphical viewports are OpenGL® based and display all the scene items (objects, cameras, etc). You can create as many graphical viewports as needed. Navigation These are the basic functions to navigate in the graphical viewports:

ALT + left button = rotate camera origin around the target ALT + right button = zoom in/out camera origin ALT + middle button = displacement of camera in the frustum plane ALT + SHIFT + left button = rotate camera target around the origin ALT + SHIFT + middle button = roll camera ALT + SHIFT + right button = displace camera origin along the look-at direction

The last function is only available when the viewport is a camera view.



Additionally, there are quick navigation options when right clicking on any viewport. Please, see the image below.

Navigation options on the right mouse button menu

“Reset viewport” will reset the viewport to a default perspective view. “Look at selection” applies both for camera and perspective views and it centers the selection on the viewport without changing the position of the viewer or the camera zoom. “Center view” options redraw the viewport and zoom in or out to adjust the selected object/ scene in the viewport. 2D / 3D Viewports Maxwell Studio provides perspective and orthogonal windows. Panels can be switched easily using the shortcuts ALT+1 and ALT+2. There are some icons over the graphical window that allows the user to change between views very fast.

The little eye is meant for changing among the perspective/cameras point of view. When clicked, a menu will appear listing all the available cameras and perspective. The “Shaded” option will change the display mode of the window. Please, see Display Modes in page 19. The button “3D” can be clicked to change to a 3D view; by default it will show the last active perspective in that window.



In a similar way, you can click to any of the other letters to have a quick access to orthogonal views. “F” stands for front, “B” for back, “L” for left, “R” for right, “T” for top, “D” for bottom or down.

3D and 2D viewports Selection: objects and other entities can be selected by clicking single objects with the left button or dragging a region with the left button pressed. Selected items will be highlighted. If there are objects behind the object selected, a second click will select the object behind the originally selected and so on. Before learning the selection modes, it is recommended to import some objects in the scene by right clicking in the viewport and choosing “Import object to scene”. Then load one or more objects. To remove the selection, click the ESC key (remember to use the ESC key to exit from different states). The objects can be also selected in the “object panel” list, clicking on the desired object or using SHIFT to select several objects.

Selecting by using a region



There are more options for selection in the “Selection” menu, such as “Inverse object selection” and “Select all objects” that are self-explanatory. And others that have more to do with display options for current selection, like “Wire Selected Objects” and “Flat Selected Objects” for changing shading mode of selected objects; and “Hide Selected Objects”, “Unhide selected objects” and “unhide All Objects” for hiding and showing certain elements of the scene. All these options, though not essential, will help speed up the workflow and that is why they are available at the menu displayed when right clicking on any of the viewports.

Selection options available at right mouse button menu

Move / Rotate / Scale In order to move, rotate or scale any objects, they must be selected previously. You can edit one or more objects at once. Switch to edition mode using the icons in the upper toolbar or using the keyboard shortcuts Q (all), W (move), E (rotate), R (scale). When the editing state is set, the axes are shown in the viewport. You can move, rotate or scale the selected objects dragging the axes or using the numerical parameters in the “objects panel”.



All, Move, Rotate, Scale editing modes Press ESC to exit the editing mode. If you have the translation handlers enabled in a selected object (key W) and you left click in any other area of the viewport, the movement is constrained to the ground plane. If you use the central button instead the movement is constrained to the vertical plane more parallel to the camera plane. Please note you can constraint to move/rotate/scale in just one axis by clicking on that specific axis, it will turn to yellow indicating you will make the translation in that only axis. To change the selection while the handlers are enabled, use the middle button instead of the left button (SHIFT + middle button will add to the selection). The new selected objects will have the handlers enable too.

Advanced Editing There are different selection modes accessible through the icons in the main toolbar or with the keyboard shortcut ‘T’. By default, the selection mode is set to “Object” which means that only objects are selected. Other available selection modes are:

Group selection: Select a group of objects (see object panel for more details about groups).

Triangle selection: This is useful to apply materials to group of faces.

Material selection: This is useful to “pick” the material assigned to an object or face. The material will be selected in the “material panel”. If you make double-click on the object, the material editor will be opened. Please note there are some special features to improve the triangle selection process: In the triangle selection mode, the user can access to different types of selections. By default it is set to “Nearest”, meaning that either by clicking on the polygons or dragging a window only the nearest faces will be selected, and no hidden face will be selected. To change the triangle selection mode, go to the “Selection” menu and choose one of the following options.



Selection menu • Key ‘+’ will expand the selection to the neighbor faces. Pressing the key ‘+’ several times will

propagate the selection to the next neighbor faces of the current selection. • Key ‘-’ will do the opposite of key ‘+’ reducing the selection to the inner neighbor faces. • Key ‘.’ (dot) will expand the selection to the faces which are coplanar to the selected ones.

This is useful to pick the whole set of coplanar faces in one specific area especially in “hidden lines” visual mode.

• Key ‘/’ (slash) will expand the selection to the connected faces. • Key ‘*’ (asterisk) will do the inverse selection. • Key ‘F8’ ‘F9’ F10’ ‘F11’ switch amongst different triangle selection modes:

• “Set expand to facet selection mode” or “Expand to facet” will select facets instead of

triangles.

• “Set raycast polygon selection mode” is called “Xray” in the viewport and makes allows the user to select both nearest and hidden triangles. To select all the triangles intersecting the mouse ray.

• “Set front-face polygon selection mode” is the same as “Nearest” explained before. It

selects the nearest triangles facing to the camera.

• “Set paint polygon selection mode” or “Paint” allows you to drag the mouse to paint the selection over the surface. Like “nearest”, use the SHIFT key to select more triangles while dragging the mouse.

There are additional controls to add or remove items to the current selection:

Add elements to the selection: click over the element with the SHIFT key pressed.

Remove elements from the selection: click the element with the CTRL key pressed.



Display Modes Maxwell Studio provides different display modes. You can choose the appropriate mode by clicking on the Shaded menu on the viewport title bar. The display modes list also includes options to visualize the textures, save the frame buffer and render the scene.

Display modes These are the specific functions to render the scene (more information in RENDERING section): • Bounding box: - only bounding boxes are shown • Wireframe: - only lines are shown • Hidden lines: - like wireframe, but coplanar edges are removed • Flat: - flat shaded visualization • Toon: - “cartoon” shading • Shaded: - smooth shaded visualization • Texture decal: - textures are previewed in the viewport • Textured: - textures are previewed in the shaded viewport • Preview: - fast preview of the scene (shortcut CTRL + P) • Render: - render the scene (shortcut CTRL + SHIFT + P) • Render region: - drag a region and render only the covered area • Capture frame buffer: - save a bitmap with the contents of the graphic viewport



Display Preferences Display preferences are found in the main menu “Edit Preferences OpenGL”. • Background color: - color of viewport backgrounds • Grid: - show / hide grid in viewports. The grid unit is in meters. • Threshold angle: - used in “hidden lines” visual mode to remove edges • Enable sky in new scenes: - always creates a physical sky by default in new scenes • Smooth AA: - enable / disable line antialiasing • Lights: - number of lights used in OpenGL viewports • Show bounding box: - acceleration mode showing the objects as bounding boxes when the

camera moves. OBJECTS Maxwell Studio accepts different object formats like OBJ, STL, LWO, NFF, XC2, DXF, 3DS, FBX AND XML (AllPlan 2005). In general all the objects must be triangulated previously since Maxwell does not work with non-triangular faces. To import objects, right click on the graphic viewport and use “Import object to scene”, then choose the object. You can also “drag & drop” the object files on the viewports directly from your explorer program. All the objects are added to the “object list” panel where they can be selected by clicking on its name in the list. There are additional functionalities such as “Create clone” in the “Edit” menu. It is a useful option for duplicating geometry. Groups Objects can be grouped by selecting the objects to be grouped and choosing “Create group from selection” from the contextual menu (right click button on viewport). Objects can be moved from groups to groups or removed from groups by dragging them in the “object list”. Also you can right click in the list to display a menu with some options. Objects can be removed from the scene using the DEL key. There are some more available options for speeding up working with groups within Maxwell Studio. To have access to them, just right click on the objects list. Please note that depending on the type of selected item, some of these options won’t be available.



The name of the object can be changed pushing F2 on the selected object name.

List of objects and groups Groups in Maxwell Studio are very important to reduce time by setting common parameters. When a group is selected, all the related parameters or actions are applied to all the objects inside that group. This is useful, for instance, for applying one material to a group of objects. When a group or a set of objects are selected in the “object list”, the “object param” panel will show the list of parameters that can be changed for that selection. Following, is a description of those parameters.



• Position: XYZ world position of the object(s) • Orientation: Euler angles of the object(s) • Scale geometry: XYZ scale of the object(s) • Center pivot: Set the pivot point to the geometric center of each object. • Pivot position: XYZ position of the pivot • Pivot orientation: Euler angles of the pivot • Hide: Hide/show the object (hidden objects are not rendered and do not participate in it) • Hidden to camera: Hide the object from showing up in the render but have it participate in the render calculation • Show normals: Show normals on each face • Normal size: The length of the normal vector in display • Object shading: Choose different visual modes for the selected objects. • Smoothing: Calculate smoothing normals per vertex • Recalc normals: Force the computation of normals. Together with the previous and next parameter, it is useful to smooth or flat faces on an object. • Smoothing angle: Angle of smoothing Below the “object param” panel, there is a list of the projectors assigned to the selected objects. See the TEXTURING section for more information about UV projectors.



The “object list” also includes information about the materials applied to each object. One object can have one or more materials applied. By default, the material is applied to all the faces of the object. The applied materials are shown as child of the objects in the “object list”.

Material applied to objects

MATERIALS: INTRODUCTION The real world of materials around us is complex. Even common surfaces like metal, wood, plastic and glass appear unique to our eyes because of a dizzying array of physical phenomena that occur. Due to the intrinsic complexity of a completely physically-accurate method of describing such optical properties, Maxwell provides two different methods to create materials: Type A: Custom and flexible physically-based materials. Type B: Advanced materials based on Complex Index of Refraction data.

(a.k.a. Complex IOR or Full IOR) TYPE 'A' Materials of type A, which are extremely powerful and flexible, are less mathematically complex than type B materials. In many cases, type A materials are nearly indistinguishable from type B versions, while rendering in a fraction of the time. The idea here is to keep a balance between flexibility, ease of use, speed and physical accuracy. The vast majority of users will work with type A materials most of the time. TYPE 'B' Materials based on “Complex IOR” (a.k.a. Full IOR) data are determined via experimentation in scientific laboratories and describe the optical properties of a material to the highest degree of accuracy. These materials have the advantage of being extremely realistic, with two drawbacks: - Long render times. The use of complex IOR data means Maxwell has a lot more math to do. Complex IOR computations require evaluation of more mathematical functions and they are dependent on view angle and on spectral wavelength as well as involving the computation of full dispersion (which by itself introduces a performance hit; taking longer to resolve image noise). This method does not allow many optimizations without sacrificing the intended physical accuracy. - Unable to customize the parameters. In other words, the user is limited only to the available materials in the complex IOR database and cannot change parameters to derive new custom materials. The material database contains .ior files to be used as Type B materials.



EXAMPLES: Suppose you work in jewellery and want to render gold (and only gold in its pure form) and you don't mind waiting longer for a high resolution image as long as the result is physically accurate in the most precise possible way; capturing the subtle effects of light and the unexpected shifts of color variations as it would if a real gold object was present. In this situation the use of a complex IOR material (type B) is best for you. On the other hand, suppose you're working on a two-minute animation of a gold robot for a TV production. In this case you need speed and flexibility. For instance, you might want the gold to look a bit redder and you might want it to reflect some blue light in areas. In this case you shouldn't use “Complex IOR” data, because these data were measured based on the pure chemical element Au which has consistent properties throughout nature. In this case you can use a type A material and work with the parameters by touch-and-feel (eyeballing) to create a material that behaves like gold in many respects but it is not true gold (Au). The use of material type A will also help speed the render (helping it resolve noise sooner). Your custom-made gold (material type A) is still following the physical laws of light for accuracy, while still being entirely customizable and production-friendly. In another example, suppose you were trying to do something as simple as red water (red liquid). If we were to use the complex IOR data, the only thing we would accomplish is pure H2O as it was measured in a lab. Strictly speaking "red water" would most likely be a solution of H2O+additives. However, to render such a red liquid, we would have to prepare an actual chemical solution, measure its properties with lab equipment and convert them to complex IOR data (material type B) and feed them to Maxwell for rendering. Of course this would be entirely impractical and therefore the use of material type A (flexible and simple) would be the logical choice. In its current incarnation, the Maxwell core engine is utilizing algorithms based on physically based models of light propagation and light interaction with various media and sensors. However, at the moment, there are several restrictions on various aspects such as: polarization, fluorescence or phosphorescence. However, Maxwell continues growing every day. MATERIAL BROWSER The material browser can be opened using the main menu (Window Material browser) or switching a panel. It is also available in the MXED, the material editor standalone version. This panel provides the way to browse the Maxwell materials available. For every MXM file found in the material database, the material browser shows a small preview of the material. Within the Maxwell installation folder there is a material database that you can browse. The materials are sorted by type in different folders.

Material browser

Assigning materials from the database to objects is extremely easy. Just drag and drop one of those materials onto a selected object or group of triangles in the graphic viewport. This action will add the material to the current scene and assign it to the object/ triangles automatically.



The material can also be dragged to the material list or to the material editor (both from the browser from studio or the MXED). In the case of the material being dragged to the list, the object or triangles do not need to be selected and the material will be applied to the scene without being assigned to any object. In the second case the material is loaded in the material editor. The material database contains MXM files. This database can contain any number of MXM files provided by Next Limit, third parties or custom materials created by the user.

Browser drag & drop operations

A = from browser (MXST or MXED) to the selected object /triangles B = from browser (MXST or MXED) to the material editor C = from browser (MXST or MXED) to the material list

MATERIALS: NEW MATERIALS Additionally, materials can be created from the scratch in different ways. These are the options available to create and assign materials without using the browser. 1. Create a New Material Click right button on the “material list” and choose “create new material”. A new material will be added to the scene. In the case of an emitter, there is a “create new emitter” option. Emitter properties can be also defined from a standard material. 2. Assign Material to Single Objects Select the material in the “material list” and drag it over the object in the “object list”.



3. Assign Material to Selected Objects Select one or more objects in the viewport. Select the material in the “material list” and drag it over the selection in the “object list” or in the viewport. 4. Assign Material to Group of Objects Select the material in the “material list” and drag it over the group in the “object list”. 5. Assign Material to Faces Enter “triangle selection” mode and select some faces. Select the material in the “material list” and drag it over the faces selected in the viewport. 6. Assign Material to Triangle Groups Enter “triangle selection” mode and select some faces. Create the triangle group by clicking on the “create group from triangle selection” (right click menu on viewport). Select the material in the “material list” and drag it over the triangle group in the “triangle cluster” panel. _________________________ The select material function is very useful in order to know which material is being used by a triangle. To do this, enter in the “select material” mode (loop selection modes with “T” key) and click on a single face or object. The applied material will be selected in the “material list”. Maxwell Studio will apply diffuse materials by default at render time to all the objects that have no materials applied explicitly. There are additional functions accessible through context menu (right click) in the “material list”: • “Select triangles associated with this material”: This is a selection clue to select all the triangles that have the current material applied. This is useful to reassign other materials. • “Add to selection triangles associated with this material”: This is like the previous function, but adding the triangles to the existing selection. • “Remove from selection triangles associated with this material”: This is like the previous function, but removing the triangles to the existing selection. • “Launch selected material in editor”: This will open the Material Editor to edit the current material (double click on the material will do the same). • “Create material from MXM”: This will create a new material importing a MXM file. • “Clone material”: This will create a copy of the selected material. • “Remove selected material”: This will remove the selected material from the scene. • “Remove all materials”: This will remove all the materials. The material name can be changed by pushing F2 on the material name.



MATERIALS: EDITING This is one of the most important areas of Maxwell. The material editor provides a powerful set of parameters for advanced editing of a Maxwell material. In the material editor we can distinguish some defined areas:

A) Material components: Maxwell’s materials can be composed of different layers and each layer include one BSDF and several coatings. Emitters are also defined here.

B) Material preview Provides a quick preview of the material.

C) Material properties: Specific optical and surface parameters for each material

component (BSDF, coatings, etc).

Material editor



Material layers

Maxwell materials can contain several layers, and each layer can include one BSDF and one or more coatings. The general scheme of a Maxwell material is like this: Maxwell Material Basic layer 1 Coating N… Coating 1 Coating 2 BSDF Basic layer 2 Coating M… Coating 2 Coating 1 BSDF Basic layer X…

BSDF stands for Bidirectional Scattering Distribution Function, and represent a very accurate optical model of a physical material. The BSDF basically represents the optical properties of the main volume of the object, whether diffuse, metallic, dielectric, or any smooth transition between those. This is controlled by the BSDF parameters. Coatings are very thin layers that are placed “on top” of the BSDF. For example, a glossy white plastic will be made of a diffuse BSDF plus a coating. The main property of the coating is its thickness. The thickness can be specified by a numerical value through a weight map. To avoid interference coloring, you have to use 1 mm (1000000 nm) thickness. Layers can be piled up and controlled through a general strength factor or a weight map, and can be set in a normal or additive mixing type. Usual materials will contain one layer, one BSDF and probably one coating. However, with this scheme there are infinite possibilities. Keep in mind that a BSDF can be any kind of material (dielectric, diffuse, metal…) and that coatings are always transparent as they are very thin. Also any of these layers can not only be a BSDF but also an emitter or a sole coating. This means a material can have a very complex scheme if the user needs it. Adding / Removing Layers In the material layer panel, layers, BSDF, emitters, subsurface layers and coatings can be created or removed using the contextual menu (right click on panel). The functions are:

• Add basic layer: This option creates a new layer with one BSDF. Only one BSDF is allowed per layer.



• Add emitter: Adds an emitter component. Emitters can be alone or coexist with layers making complex materials that can be switched on and off revealing its base material or emitting light (like an incandescent metal). • Add coating: Adds a new coating to the selected layer • Add subsurface: Adds subsurface properties to the selected layer (only one per layer is allowed) • Embed MXM file: Imports a MXM file into the current material. • Reset layer: Restores default parameters in current selected layer. • Delete layer: Deletes the current selected layer Basic layer properties The only layer property available is a weight value or weight texture. This weight value controls the way different layers are blended together. For example, if there are two layers, setting 50 for both layers will produce a 50% contribution of each layer. The weight texture can produce different blending effects. For having a visual clue of the weight of each layer, its value is displayed in the material layers list. The order of the basic layers does not interfere in the material behavior. The contribution of each basic layer is only determined by its weight and the blending mode enabled.

A complex material made from several basic layers blended together. As seen in the image above, each layer can be composed of different types of properties. BSDF properties When a BSDF is selected in the material layer, the BSDF properties are displayed in the right panel. There are two set of controls for controlling the material properties and the surface properties.



Material properties

Reflectance 0º / 90º: is the light reflected by the material. Choose a reflectance color by clicking the color picker, or specify a texture by clicking in the texture button . You can enable or disable the texture using the check button near the texture button. A white reflectance means that all the light is reflected. Black means that all the light is absorbed. Red means that only the red component of light cast on this object is reflected. There are two reflectance colors depending on the light reflected when the object is seen at 0º degrees (frontal view) or at 90º degrees (glancing angle). This different reflective effect at different angles is known as Fresnel effect (an increase in reflection and decrease in transmittance at glancing angles). Usually the reflectance 90º color is white for normal objects, however you can change it to allow different reflected colors in the edges of the object like in the samples below. The Reflectance 90º is also known as the Fresnel color. Different combination of reflectance 0º and 90º are shown in the next figure:

Different Fresnel colors

Transmittance: Controls the light that can pass through the object and how it attenuates. Choose a transmittance color by clicking the color picker, or specify a texture by clicking in the texture button . The transmittance color represents the light obtained when the light has reached the attenuation distance (see below).

Attenuation distance: This parameter is closely related to transmittance and controls the strength of the attenuation. If the attenuation distance is very small (1 nm), the object will be opaque, conversely if the distance is large, the object will be almost transparent. The attenuation is ruled by an exponential curve, therefore, the thicker the object, the more attenuated the light will be, like in the following example:

Thicker areas are more attenuated



To better understand the concept of attenuation, consider sea water. When the water layer is very thin (like water in the palm of your hand) you don't see attenuation and get rather transparent water, when you have enough water thickness, you see a typical sea color (dark or light blue-green, depending on deep or shallow waters). The transmittance color represents the color that you want to get approximately at the attenuation distance. Beyond this distance, the light is more and more attenuated and can eventually vanish (black).

Blue transmission color / Attenuation distance (18 cm) / No roughness (1)

Blue transmission color / Attenuation distance (18 cm) / Medium roughness (40)

Transmission map / Attenuation distance (18 cm) / Medium roughness (40)



Technically, when a reflectance and a transmittance color are chosen, they are converted to energy spectrum inside Maxwell (remember that Maxwell does not use colors internally). Reflectance and transmittance are dependant properties. Maxwell’s mathematical robustness requires that some physical properties like the energy are conserved. Therefore, the reflectance and transmittance colors are corrected according to this. You can see a second color square which is the corrected color. Placing the mouse over the squares will show a tooltip with the numerical RGB values.

(Custom IOR) ND / Abbe: For transmitted light, the ND / Abbe options control the refraction properties. ND is the known index or refraction (for example 1.33 for water).

Even if the object does not transmit light, ND is still very important. A low ND value like 1.00 means light will not be reflected, regardless of viewing angle. On the other hand, a high ND value (80.00) will cause the light to be reflected in a uniform manner, also regardless of the viewing angle.

So, if the reflectance must be homogeneous, the ND must have a high value to prevent decay in reflection on facing polygons. Just make a simple test and set ND=100 and compare it to NDd=1.0, you will notice that the first case is more glossy (less rough) material. From Roughness 0 to 100 this phenomenon decreases exponentially.

Reflectance 90º will also affect the maximum strength of reflectance at glancing angle. Thus, both reflectance colors change the strength and color and ND (fresnel) affects the ramp of gradient. As mentioned earlier, ND is not only useful for refraction effects (transmitted light). ND also affects the way the light is reflected at different view angles (Fresnel effect). Let’s see some examples using a black sphere with ND 1.0, 1.2, 1.5 and 20. By increasing the ND value, the light reflected at glancing angles increases too.

Therefore, the Fresnel effect requires na ND value greater than 1.0. Abbe controls the spectral dispersion strength (the higher the Abbe, the narrower spectral dispersion). Spectral dispersion will raise the render time; therefore it is disabled by default. In order

to enable dispersion, click on this button on the top right part of the material editor.



Spectral dispersion

Load file: This option allow us to include an .r2 file to have a maximum control of the fresnel effect over the surface.

Load full IOR data: As an alternative to the ND and Abbe values, you can use an .ior file which provides Maxwell with the exact index or refraction for each wavelength (see page 88 for more information about these files).

Surface properties

Roughness: The roughness of the surface from 0 (perfectly smooth surface) to 99 (almost pure diffuse). The Lambertian check will use a perfect diffuse model (like 100% roughness). You can also set a texture to control the roughness. In order to control the roughness when using a texture keep in mind that white means higher roughness (more diffuse). Also notice that when using a texture you can adjust the whitest point on the texture with the value on the parameter. Let’s imagine you have a checker map and a value of 30, White squares are 30 roughness while black are 0. If you change the value to 70, white squares will be more diffuse than in the previous example but black ones will still be a perfect smooth surface. So, roughness value is a top limit when using a texture. Roughness rules the behavior of the material in a very important sense, allowing a smooth transition between very polished surfaces like mirrors to glossies (metals or plastics) and very diffuse surfaces. Usually this parameter must be considered as important as the reflectance, transmittance and attenuation factors.

Anisotropy: Specify anisotropy strength (0 for isotropic surfaces – 100 for full

anisotropy). The anisotropy of the surface controls the preponderant directions of the reflected light in non-homogeneous materials. You can also set a texture to control the anisotropy.

Angle: Specify the anisotropy angle (the preponderant direction of reflected light).

You can also set a texture to control the anisotropy angle.

Bump: Specify a bumping texture and the bumping strength. There is an additional option to specify a “normal bump” texture. The normal bump works by using the RGB components of the texture to alter the direction of the normal vectors while the traditional bump only uses the intensity of the color. Bump is a very sensible parameter and standard values will go around 20.



Clipmaps using transmittance mapping The transmittance map can be useful to simulate clipmaps. Clipmaps are defined by a black and white bitmap used as a transmittance map. Remember that the transmittance color is defined as the color obtained approximately at the attenuation distance. However, there are two exceptions: • If the transmittance color is pure black (RGB 0 0 0) the object is considered opaque. • If the transmittance color is pure white (RGB 255 255 255) the object is considered transparent.

Clipmap example BSDF examples These are some basic examples; of course there are infinite variations:

Opaque diffuse object: · any reflectance color · transmittance black · very high roughness value or Lambertian.

Opaque glossy object: · any reflectance color · transmittance black · medium roughness value



Transparent water: · reflectance black or very low · transmittance white · high attenuation distance (999 m) · ND=1.33 · minimum roughness value (0.0)

Very polished metal or mirror: · any reflectance color · transmittance black · Minimum roughness value (0.0).

Mild polished metal or mirror: · any reflectance color · transmittance black · Low roughness value (10.0).

Tinted transparent object: · reflectance black · any transmittance color · ND = 1.0 · medium attenuation 1 cm · Minimum roughness value (0.0).

Coating properties The coating properties are almost the same as the BSDF properties. The main differences are:

Thickness: This is the height of the coating (in nanometers). The thickness can be also controlled by a thickness map. Interference effects can appear in the coatings depending on the thickness. The interference patterns appear when the thickness of the coating is close to the wavelength incident light (or a close multiple of this value). The visible band of the spectrum is in the range 380- 700 nm so if you want to avoid interference patterns increase the thickness of the coating a lot. 1 million nm will give you 1 mm thickness and no interference.



Different thickness on coatings

There are no surface properties (coatings are in essence very thin reflective layers, like a bubble, that have no specific surface properties defined). The order of coatings inside a basic layer is essential for the optical properties of the material. Coatings can be drag & dropped and rearranged within the same basic layer or across different layers. Subsurface properties Subsurface scattering (SSS) properties can be added to each BSDF in a one per one basis. • Absorption: Defines the amount of light to be absorbed through the object surface. When raised, surface gathers more light inside. • Scattering: Defines the amount of light to be scattered back from sub-surface. When increased, the surface will become more translucent.

Subsurface scattering effects Emitter properties The emitter layer provides the object the ability to emit light. There are specific parameters to control the light emission. • Input: This is the most important one as it defines how the user must specify the emission. There are several possibilities.



Color + Luminance

Emitter properties. Input: Color +Luminance

• Color: This parameter refers to the color of the light emitted. There are two ways in which you can specify the color.

- RGB that stands for Red, Green and Blue. Clicking on the colored square allows the user to choose a color in the Maxwell color picker.

- Correlated color at: Lets you choose the color that would correspond to an emission

of the numbers of Kelvin degrees specified. Please note that choosing this option will not make any changes on intensity, just color. Low Kelvin temperatures are reddish colored and when raising they tend to be white. If higher, emission will turn into a blue tone.

• Luminance: This parameter is used to specify the intensity of the light. There are several ways the user can choose.

- Watts and Efficiency. In everyday life we have seen bulbs intensity measured in Watts. These watts are the power the bulb can supply. This energy emitted by the light source is not only emitted in the form of light it but also in the form of heat and other types of emission. These other emissions which are not visible light are called losses. The Efficiency is measuring those losses, the higher the efficiency the lower the losses, to a maximum of 683; which is the value where 1 watt will emit 683 lumens (no energy losses). Just to give an idea, a tungsten lamp has got an efficiency of around 13.

- Luminous power: Lumen (lm). Lumens are a very common way to measure the light. It is normal to see recommendations on lumens for certain jobs or ways.

- Illuminance: Lux (lum/m^2). Luxes are also a very common way of measuring the

light.

- Luminous Intensity: Candela (cd). A different way to specify the light.

- Luminance nit (cd/m^2). • Load Preset: Maxwell provides some presets that can come very handy.



Temperature of emission

Emitter properties. Input: Temperature of emission

A temperature in Kelvin degrees can be chosen. This will affect not only the color but the intensity of the emission. A higher temperature will make the emission more intense and the color will change from red to orange, to yellowish, white, to blue.

Emitters at different ºK temperatures

MXI texture

MXI is the Maxwell image format, it stores high dynamic range data and has a lot of advantages over others high dynamic range formats, like the possibility to store a render in this format and resume it later on. For more information on MXI format please go to page 65.



So, this emission option allows us to texture an emitter with an MXI/HDR map so that the objects pick up the intensities and colors of each pixel to emit accordingly to this information.

Emitting materials Besides how the emission is specified, emitter layers can be blended with other materials, allowing the user to turn a material on and off, as if it were incandescent.

Material + Emitter layer and glass emitting light

Blending layers There are two modes in which the layers can blend, normal and additive. You can change to one or the other by the “N” button at the top right part of the material editor.

When normal mode is chosen, layers will blend together like a mix; contributing to the mix depending on its weight. Maxwell will internally normalize the values, not allowing the energy system to break. This normal blending mode is physically accurate. In additive mode, layers blend together adding their values to the material rather than mixing. The layers will contribute to the blending depending on its weight too, as in normal mode. However, the difference is that Maxwell will not normalize any value here, so we can reach a non-physical solution; like a system where a surface is reflecting more light than it is receiving. For example, blending two BSDF with high reflective color in additive mode can lead to non-physical solutions.

Material preview This panel shows a preview of the current material. To preview a material, click the icon in the upper right side of the material editor, double-click on the preview image or use the CTRL+P shortcut. Additionally, doing a right click on the material preview, you can access some specific options:



Right click on the material preview • Load scene to preview: This window can preview any MXS file. It uses a default MXS (defaultpreview.mxs file in the preview folder). • Set preview options: This option specifies the quality and number of bounces of the preview engine. Complex materials may require higher quality properties. These options are also available in the Preferences panel. There are two engines you can use, the preview one called RSO and the final one you will use at rendering, called RS1.

Preview options The material preview window can actually contain any MXS, this is useful to preview specific scenes or objects. When the right click menu is shown, all the MXS files available in the preview folder are shown, letting you to choose the desired one.



CAMERAS By default Maxwell Studio has a perspective visualization mode that acts like a camera, but without all the possibilities of a real Maxwell camera. Creating a camera Use the viewport menu (right click on viewport) and choose “create camera” or press CTRL+C. This will add a camera with the point of view of your perspective. You can create as many cameras as you want. Once a camera has been created, the camera frustum is displayed on the viewport. To switch to a camera viewport, click the “eye” icon in the upper left corner and choose the desired camera.

Camera frustum

The camera frustum is adapted according to the resolution of the image set in the “camera panel”. When the render is launched from the camera view, only the region inside the frustum is rendered. When the render is launched in the perspective view, the whole viewport is rendered. The “camera list” panel contains a list of all the cameras. Selecting any camera in the “camera list” will also display the camera properties in the “camera params” panel (remember that “camera list” and “camera param” are different panels).



Camera list and camera parameters panels The camera can be displaced in the 3D world by switching the viewport to “camera view” and rotating, displacing or zooming the view as explained before (ALT + mouse). This mode affects the origin of the camera (“From”). In order to displace or rotate the target of the camera (“To”), use the shortcut ALT + SHIFT + mouse. The following are the specific camera options: • From: XYZ world coordinates of the origin of the camera

• To: XYZ world coordinates of the target of the camera • Roll: Rolling angle of the camera (in degrees) • Shutter: The shutter speed, specified in 1 / n of a second. • fStop: Controls the aperture of the lens (see image) • Focal length: The focal length of the camera. • Film height: Camera film height. • Film width: Camera film width. • ISO: Sensibility of the film (the higher ISO the higher sensibility) • Resolution: The desired resolution of the rendered image • Pixel aspect: Width-height proportion of the pixels • Diaphragm type: Choose Circular or Polygonal • Blades: Number of blades (for Polygonal diaphragm) • Angle: Angle of the blades (for Polygonal diaphragm)



Camera focus Maxwell’s cameras work like the real cameras, blurred or sharp images can result if the target area is out of focus. In order to adjust the focus of the camera, there are some visual clues in the graphic viewport. First consider the following image: The camera is pointing to the interest area (the koala). The focal distance should be the distance to the object in order to get a perfected focused image. The near and far planes define the DOF area. Inside the DOF area, all objects are in focus.

The Maxwell camera has a visual focus indicator that provides information about the focus conditions of the target. When the camera moves, the focus indicator changes according to the distance to the objects pointed by the camera and the camera properties. The focus indicator is composed of two circles and a rectangular indicator just in the center of the camera. When the target object (the central point of the circles) is exactly in focus, the rectangular indicator turns to yellow, otherwise it remains black.

A black indicator does not mean necessarily that the render will be out of focus, it also depends on the DOF distance. To measure if the camera target is inside or outside the DOF distance, the circles use blue or red colors. The area of the circle with red color means than the specific target area is beyond the far plane. Conversely, when the area of the circle is blue, the points are before the near plane. Areas in red and blue mean “out of focus” zone. Transparent areas are in focus. The yellow mark is the exact focal point.



The numbers near the focus indicator refer to: FD = Focal distance Near = Distance from camera to near plane Far = Distance from camera to far plane DoF = DoF distance (Far – Distance) Use the shortcut: key ‘I’ to disable or enable this information in the display.

Focus indicator showing focus and out of focus areas

Render

Two additional functions “Auto focus” and “Focus to” are very helpful to control the focus of the camera. You can find these options in the right click menu. • Auto focus (key F): Automatically focus the target point.



• Focus to: Click on this and then click any point of the viewport. The clicked object will be in focus without changing the camera target.

SKY OPTIONS Environment options in Maxwell Render are grouped under the Sky options panel. The most important parameter in this panel is “Sky type” for choosing the environment among these next options.

Sky Dome: This option represents a virtual sky on our scene, a uniform color sky.

• Set Sky Color: Clicking on this button will pop up a color picker to choose the dome color.

• Lumens: Type the intensity of the dome in lumens.

Physical Sky: Maxwell Render provides a physical sky model that reproduces the skylight conditions at different hours of the day. When the sky is enabled, the viewport shows a visual representation in OpenGL that can be enabled and disabled by pressing the ‘K’ key.



• Enable sun light: The sun can be enabled or disabled independent from the sky light. • Latitude / Longitude: Earth positions to calculate the sky light. • Day / Hour: Set julian day (0-364) and hour of the day to calculate the sky light. Press “Set date and hour” to load your current clock time. • GMT offset: Set the Greenwich Mean Time offset of you current location. • Turbidity / Ozone / Water: Physical properties of the sky, slightly affect the color components of the sky. You can interactively rotate the Earth in the display, to change to a different location. Shortcut: CTRL + K enable/disable the sky representation in the graphical viewport.

Compass and sun direction



The graphical viewport shows the geographical directions (N, S, W, E) by means of a compass located in the bottom left corner. The sun is represented by a small yellow sphere that points to the sun direction. When the sun is below the horizon, the yellow sphere fades to black.

MXI/HDR Map: Setting an image based spherical environment. The two formats allowed stores high dynamic range data, therefore they are set not just an environmental image but as an emission spherical map around the scene. Note that there are several available channels where to put mxi/hdr maps; this is a very powerful feature as it allows the user to have more control over the effects of the environment on the scene.

MXI/HDR sky options

• Background channel: Allows the addition of an MXI/HDR map as a background environment, not for emission purposes but for a background on the scene. • Reflection channel: Allows the addition of an MXI/HDR map for reflections on scene objects. • Refraction channel: Allows the addition of an MXI/HDR map for refractions on scene objects.



• Illumination channel: Allows the addition of an MXI/HDR map as a background emission. Each channel can be edited separately. • Texture: For selecting the MXI/HDR map. • Disable channel. • Intensity: Set the importance of the current channel. • Scale: For scaling the current map. • Offset: For rotating the spherical environment. Sky used in disabled channels adds an extra control over the environment.

None: Disable sky.

RENDERING There are several ways to control the rendering process within Maxwell. As explained before, Maxwell provides an external rendering tool (MXCL) which can be called providing an MXS scene to render. MXCL can be called from the 3D applications, using the plugins available for the supported platforms, or from the command line, using the basic form: mxcl –mxs:scene.mxs The render can also be launched within Maxwell Studio very easily, just choosing the appropriate rendering method in the graphical viewport menu: Preview, Render or Render region.

Viewport visual modes

When “Preview” or “Render” is clicked, the render process is launched in the graphical viewport. Depending if a camera or perspective mode is active, the render will cover only the camera frustum or the full window. Also, the render can be launched from an orthographic view. To cancel the render process, click on any point in the viewport.



Shortcuts:

CTRL + P = Preview (RSO Engine) CTRL + SHIFT + P = Render (RS1 Engine)

Preview in perspective view

Preview in camera view

The “Render region” mode allows selecting a region of the screen previous to launch the render process. This is useful to focus on specific areas of the screen.



Render region

Additionally, there is an option to export the scene to MXCL, the standalone rendering tool. You can do that by pressing the icon in the main menu. By doing this, a temporal version of the current MXS scene is saved in the default scene folder, and MXCL is called to render that scene. By default, Maxwell Studio provides a general lighting including a physical sky in the scene. This option can be changed in preferences. Additionally, all objects or faces without assigned materials are rendered as diffuse.

The “Render options” panel shows the different controls related to the rendering process: • Render time: Set the maximum render time (in minutes) for the render. The longer the time is, the cleaner and more accurate image you will obtain. • Render threads: Number of threads dedicated to the render. By default 0 threads means that all available CPU are used. In special situations you may require less threads if the machine is working in other tasks. • Sampling level: Maximum sampling level required. This value controls the quality of the render. As with the “render time” parameter, the higher sampling level reached, the more accurate image obtained. Unfortunately, the render engine needs time to reach higher sampling levels (usually the next sampling level takes more time than the previous one). Maxwell will finish the rendering process when one of these conditions “Render time” or “Sampling level” is met. If you really want to finish at some specific render time, set a very high sampling level, and conversely, if you want to reach a specific sampling level, set a very high render time. • Burn: A tone-mapping parameter that controls how fast the image is overexposed. • Gamma: A tone-mapping parameter that controls the monitor gamma of the output image. • Autoexposure: A tone-mapping parameter that automatically controls the monitor gamma of the output image. The Autoexposure option helps to avoid losing contrast when raising the dynamic range, it makes a better balance between range and contrast. • Scene scale: general scale applied to all objects when they are sent to the render engine. • MXCL render path: Set the path and filename for the render output when MXCL is launched



• MXST render path: Set the path and filename for the render in Maxwell Studio (default: current scene folder) • Bounces for preview: Number of bounces for the preview (the higher, the slower and more accurate preview) • Preview priority: Set the priority of the preview process. • Render in low priority: Starts the render process in low priority to reduce the CPU load. • Command line: Textbox where you can enter any command line option (please refer page 59). Any of the commands entered here will overwrite the render options. As an example, you can render to a test resolution from command line without losing the final render parameters specified in Resolution parameter in camera properties. Also, this is the place to enable the multilight function in Maxwell Studio (please refer to page 67). Just type in “–ml”. Layers allow the user to choose whether to render direct lighting, indirect lighting or both. Just enable the layers you do want to render. Render time could be slightly reduced when disabling any of these layers. • Layers - Direct: Enables the direct lighting render layer • Layers - Indirect: Enables the indirect lighting render layer Caustics layers are similar to layers. Render time could be slightly reduced when disabling any of these layers. • Reflection caustics - Direct: Enables the direct reflected caustics (if direct layer is enabled) • Reflection caustics - Indirect: Enables the indirect reflected caustics (if indirect layer is enabled) • Refraction caustics - Direct: Enables the direct refracted caustics (if direct layer is enabled) • Refraction caustics - Indirect: Enables the indirect refracted caustics (if indirect layer is enabled)



Render options Channels are a special feature for rendering passes. Calculating more channels will take extra time at the beginning of the rendering phase. The output will be set in the MXCL Render Path with a suffix. • Main – Render: Enables the option of saving the render of the scene. • Main – Alpha: Enables the option of saving an alpha pass for the scene. • IDs – Object: Enables the option of saving an image with objects silhouettes. • IDs – Material: Enables the option of saving an image with materials silhouettes. • Z Channel: Enables the option of saving an image representing depth within the two values specified in Z buffer range. • Z Buffer range: Distances range for Z Channel.



MAPS AND TEXTURES Maxwell Studio provides built-in features to map textures to objects using different map projectors. Maxwell Studio also reads the UV mapping information exported from the 3D applications by the Maxwell plugins. In order to texture an object, we need to introduce the concept of a map projector first. A map projector is an object property that tells how to map a flat bitmap onto the object surface. There are different kinds of canonical projectors: cubic, spherical, cylindrical and planar to project the bitmap according to the desired effect.

Cubic, spherical and planar projections Creating a map projector In order to create a map projector for an object, select the object and right-click the mouse to access the contextual menu. Then click on “create projector”.

The new projector will be added to the projector list at the end of the “object param” panel. It will also be added to the “projector list” panel. Therefore there are two ways of accessing a projector, for a given object: through the “object param” panel or through the “projector list” panel. The “object param” panel only lists the projectors created for the selected objects (a single object or a set of objects). The “projector list” lists all the projectors existing in the scene. In the next image you can see these areas marked in red. Every projector contains a set of editable parameters. These parameters are available in the “projector param” panel. You can add as many projectors as you want for a single object. Every projector will use a “projection channel”. The projection channel is useful to connect maps and textures from materials.

OBJECT PROJECTOR CHANNEL ID MATERIAL TEXTURE

Typically, the material will require a “Channel ID” to assign the texture. Once this has been done, the texture projection can be adjusted by changing the projector properties. By default, a texture reference is displayed to see the projection.



Projector related panels: Projectors list, Projectors params and Object params.

Projectors parameters

The “projectors param” panel contains the properties of the selected projector. The common properties are:

• Projection type: Set the type of projector required. The projector will be displayed in the screen according to its type. The “Locked” projector is used to refer to UV channels imported from the 3D applications. • Channel ID: The channel ID used by this projector. This is an important parameter. Altering the channel ID will affect the relation with assigned textures from the materials. • Adjust: This button will adjust the projector to the size and position of the object.



There are some other options related to different kind of projectors: • Position: Displacement of the texture • Tile U / V: Enable tiling options • Scale U / V: Scale of the texture in U/V directions • Lat / Long: U and V ranges for spherical projectors Applying textures Creating the projector is only the first part of the process to apply a texture to an object. Once the projector has been added, the texture must be applied from the material. In the following image, the basic steps to apply a texture are shown:

1. Create the material and assign it to the object (step 1)

2. Open the material editor (step 2) 3. Choose the texture that you want to add, for example, the reflectance texture and click

in the texture icon. (step 3)

4. When the texture picker window is opened, load a bitmap using the Load button (step 4)

5. Finally, check out the “projection channel” that will be used for this texture (step 5). The texture will use the UV projection channel specified in this window.

6. In order to adjust the projection, you have to use the “projection param” panel.

7. Try also the options within the texture picker to adjust projection (please refer to page

56).

Assigning a texture (above) and adjusting the projection (below)



Textures are loaded using the buttons and enabling/disabling them with the check button close to it. When a bitmap file is not found, Maxwell will search for it in the current project path, in the default image path set in the Preferences dialogue, and in the Maxwell installation folder under “materials database/texture” folder. Texture Picker By now you probably have been using the texture picker, but let’s have deeper look into it in this section. To choose a bitmap, click on Load or drag and drop it from your explorer into the main frame. Please note that you can drag and drop multiple textures at once. This will make the textures available for selecting in the drop down menu. In the same way, select a previously loaded texture and click Unload button to get rid of it. The next step would be to choose a projection for mapping the texture onto the object that has this material. Thanks to the Projection ID, a material with textures can be applied to different objects. For more information on projectors please go to the beginning of this section. Finally, there are some tiling, offset and invert options for helping adjusting the current texture.



Maxwell Texture picker Color Picker Maxwell color picker it is a simple and fast tool for choosing colors. The circle on the outside colored wheel lets the user rotate the triangle inside, choosing the hue. The second circle lets you choose value and bright within the hue selected. Besides that, you can specify the color in HSV, RGB or XYZ coordinates with the text boxes below the chromatic graph.

Maxwell color picker



MAXWELL MATERIAL EDITOR STANDALONE (MXED) _______________________________________________________________ MXED is the standalone version of the Materials Editor + Materials Browser. For more information about them, you can check the correspondent sections in the manual. MXED is connected to the plugins so the user can edit their materials when setting the scene up in their 3D application without the need to go to Maxwell Studio. It is also used for creating material libraries. Several instances of MXED can be open at the same time, allowing a great flexibility among Maxwell Studio and Material editors, as it allows the user to drag and drop from the browser to the Material Editor or to Maxwell Studio and also allows the comparison of materials properties.

MXED: Maxwell Material Editor + Material Browser



MAXWELL RENDER ENGINE (MXCL) _______________________________________________________________ MXCL is the standalone rendering engine. MXCL can be used directly from command line, from Maxwell Studio or from the 3D applications’ Maxwell plugins. In order to check that Maxwell Render has been properly installed, type “mxcl” in a command line window. MXCL Commands should be listed like in the image below (windows OS):

Following are the MXCL command line options: -display -d

Opens a window and displays the render in progress.

-time:M -t:M

Specifies the time (M = minutes) that Maxwell is allowed to use to render every frame. This is a very interesting feature. Maxwell can render the scene in a specified amount of minutes, providing the best possible quality. Example: mxcl -mxs:scene.mxs –time:10

-threads:N -th:N

Specifies the number of threads (N) that Maxwell is allowed to use. Normally this should be equal to the number of CPUs available in the system. By default,t N is the number of CPUs found in the system except in cases where hyperthreading features are available. When N is 0 (-th:0), Maxwell uses the maximum number of threads (processors) available.

-res:WxH -r:WxH

Specifies the resolution of the render in pixels (W=width, H=height). Example: mxcl -mxs:scene.mxs –res:640x480

-animation:A;B-C;D -a: A;B-C;D

Specifies a sequence of frames to render. This can be provided in the form of individual frames separated by a semicolon (3;5;7) or a range in the form A-B (from frame A to frame B) or a combination of both. Example: mxcl -mxs:scene.mxs –a:3;17-32



-output:filename -o:filename

Specifies the full path and name of the image file. By default, Maxwell always saves a file ‘default.tga’ in the output folder of the installation path. The file name can refer to any of the multiple graphic formats supported (tga, jpg, tif, png, etc). In case of sequences, the output files will be numbered with a 4-digit suffix. Example: mxcl -mxs:scene.mxs –o:c:\images\scene.jpg

-sampling:level -s:level

This value establishes a quality level for the render. This value is useful when you want to render a sequence of frames using different hardware configurations. If the quality level is reached before the “maximum render time”, then the render ends. Alternatively, if the maximum render time is reached before the sampling level, the render also stops the calculus. To have an idea of the image quality during the render process you can take a look to the command line window, where the sampling level is being actualized during the render process.

-layer:a,r,z(m,M),c -l:a,r,z(m,M),c

This option establishes the different layers that Maxwell can export: a = alpha channel r = render c = cos-angle channel (cosine of angle between the camera view direction and the normal vector in each pixel). z = depth layer (“z-buffer”). This option also requires two additional values (m = minimum, M = maximum) indicating distances from the camera. The z value is then calculated by centering on the focal point (distance 0). Note that when the layer option is set, the r option should be added to obtain the rendered image (if required).

-mxi:filename,resume -mxi:filename,r

When rendering, Maxwell writes a special MXI file that contains information about the rendering process. MXI is the high dynamic range Maxwell image format. This lets the user to resume a previous render work. (Available in a next add-on) If this switch is not used, it will use the same name and path as the MXS scene. The resume option continues the render from a previously saved MXI file. In order to resume a previous render job and update the MXI file, “,r” option must be added. The MXI file is useful to resume the rendering process later or use it as a light emission map.

-p:low -priority:low

Set Maxwell priority to low.

-server This option starts Maxwell in SERVER mode, allowing distributed render tasks. For more information read the section related to network rendering.

-manager This option starts Maxwell in MANAGER mode, allowing distributed render tasks. For more information read the section related to network rendering.

-nowait Returns control to the console after the render finishes



-hd -harddisk

With this option enabled, Maxwell uses the hard disk to store part of the calculations and save memory. This option allows rendering at high resolution. (Available in a next add-on).

-bitmaps:path -b:path

Set an alternative path for bitmaps location. If path is 0 (-bitmaps:0), Maxwell will discard all the bitmaps.

-rs:N Specifies the render engine to be used. -rs:0 Preview Engine -rs:1 Production Engine (by default)

-ml Enables multilight function storing an mxi file with all the emitters’ information.



MAXWELL VIEWER MXCL provides a standalone graphical interface that controls the rendering process called “Maxwell Viewer”. This interface is opened when the option –display or -d is used. The Maxwell Viewer provides a visualization of the render in progress, and some controls to tune the image while the render is in progress (tone mapping). MXI is the Maxwell’s high-dynamic range image format (similar to HDR). MXI files are useful to resume the rendering process at a later stage or to be used as HDR-like emitter maps. The Maxwell viewer can read standard image formats (TGA, BMP, PNG, etc) or HDR images and convert them to MXI.

MXCL interface

Menu Functions These options are useful to load and save MXI files. Bitmaps and HDR files can be converted to MXI files. An MXI file can be used as a light emission map in Maxwell.

• Open MXS: open a MXS file for rendering. Press the icon to start the render. • Open MXI: open a MXI file for viewing and modifying • Save MXI: save a MXI file • Cooperative MXI: lets you manually merge a group of mxi files generated in cooperative

render more • Load Image: load a bitmap (it can be saved as an MXI) • Save Image: save a bitmap • Exit: Exit program Toolbar • SL = Current sampling level • Next SL = Time to next sampling level • Update = Time to next image update between samples • Time passed = Total time elapsed • Time left = Time left to finish • Benchmark = Maxwell benchmark number (higher means faster / scene dependant)



This button enables/disables the render preview.

This button resumes the render (only available if mxi file is available).

This button stops the render Console / Scene Data Panel These panels provide information about the rendering process, scene statistics, etc. Check it to know the status of your render.

Console tab

Scene Data tab



Render Options Panel This panel shows the rendering options that can be adjusted in MXCL. Most of these options can be set from the command line and have already been explained (see the command line options table and Render options in MXST section), however we give a remainder below the image.

Render options tab

→ Input parameters • MXS: Path and scene to render

• Time: Set the maximum render time (in minutes) for the render. The longer the time is, the cleaner and more accurate image you will obtain. • Sampling level: Maximum sampling level required. This value controls the quality of the render. As with the “render time” parameter, the higher the sampling level reached, the more accurate the image obtained. Unfortunately, the render engine needs time to reach higher sampling levels (usually the next sampling level takes more time than the previous one).

Maxwell will finish the rendering process when one of these conditions “Render time” or “Sampling level” is met. If you really want to finish at some specific render time, set a very high sampling level, and conversely, if you want to reach a specific sampling level, set a very high render time.

→ Output image settings • Image: Path and file type of final image

• Resolution: Size of the final image. • Lock Aspect Ratio: To maintain the proportion of the resolution.

→ Layers. Also referred like Channels • Render: enable the option of saving the render of the scene.

• Alpha: enable the option of saving an alpha pass for the scene. • Id Material: enable the option of saving an image with material silhouettes. • Z Buffer: enable the option of saving an image representing depth within the two values specified in the buffer range (text boxes aside).

→ MXI • Resume: Allows resume function and select the current .mxi

• Enable multilight: Stores a bigger .mxi for using for the multilight feature (see multilight section).

→ Bitmaps • Disable bitmaps.

• Default Path: Path where MXCL will look for textures and bitmaps. → Hard Disk (Available in a future add-on) • Max Memory: Allows allocating hard disk memory to render big sized images.



→ Animation

The user specifies a range of mxs frames to be rendered. For example: 5,8,9 will render frames name0005.mxs, name0008.mxs and name0009.mxs. The specified range will be displayed as 5-9.

Preview / MXI Panel These controls can alter the rendering process in a dynamic way. A small preview of the image is shown in real-time when a “Tone Mapping” or “Camera” value is changed. Due to the intrinsic features of the Maxwell engine, the render process is independent of the tone mapping, ISO and shutter values, and can be changed at any time, even once the render is finished. Maxwell will update the render image using the last edited values when the image is refreshed (Update time). The MXI options are only useful to adjust MXI files.

Preview/ MXI tab

→ Camera • Film ISO: Sensibility of the film (the higher ISO the higher sensibility) • Shutter (1/s): The shutter speed, specified in 1 / n of a second. → Tone Mapping: change the dynamic range of the images.

• Mode: there are two modes of changing the Tone Mapping. Simple is the standard method and Advanced is an special method where Maxwell measures the light of the image to adjust a better balance between range and contrast. • Burn: is a tone-mapping parameter that controls how fast the image is overexposed • Monitor Gamma: is a tone-mapping parameter that controls the monitor gamma of the output image.

→ MXI • F-stop: Controls the aperture of the lens. • Intensity: Intensity of the emission map. → Glare. Glare/bloom/diffraction happens when light goes through small holes, and then behaves like waves. It is very important in optics, as it explains why a perfect telescope ( or microscope ) that can take a photo of a star and render it as a single dot instead of some circles or streaks does not exist.



Diffraction effects on a simple render

• Aperture Map: The shape of the diaphragm will model the pattern of light that reaches the film. For example, a circular diaphragm will create circular patterns; a hexagonal diaphragm will create 6 light streaks. You can set the diaphragm shape using a black/white map (it can be a color one) called the aperture map.

Some aperture maps • Obstacle Map: This "paints" these obstacles that light will find when entering through the diaphragm and causing diffraction too, such as water drops, eyelashes, dirt, etc. Again, a white/black map is needed. If you don't want to use an obstacle map, you can use a white map, or just not set any obstacle map in the path.

Obstacle Map example

• Intensity: Controls glare intensity

The obstacle map and the aperture map, they must both have the same resolution. The render resolution and the maps are not necessary to have the same resolution, but the more similar they are in resolution, the less diffraction distortion. Increasing the resolution of the final image will drastically increase the memory and the computation time. For a 3000x3000 HDR it can need around 2 or 3 minutes to compute, and 600 Mb of RAM. But if the image comes from a MXI or a render, a 1000x1000 will take the same time and same memory.



→ Multilight • Lights: Each light of the scene is assigned a number and the slider lets the user to adjust its intensity. Preview will show changes in real time. And pressing Refresh, render will update to new values. Note that if you are adjusting lights as a post-process (once the render has finished) you might need to save the final image with the new changes manually from File menu.

Preview controls A more advanced light editing is available at the Multilight tab, described in the next paragraph. When using the advanced tool, Multilight should be disabled.

Multilight Panel This panel is a more advanced tool for editing lighting. It allows changing the intensity of individual lights in the scene affecting the global illumination and lighting. This is not only a tool or adjuster but a real composer where the user can make a video animating lighting, with a single render. This process can be done either while rendering or once it is finished. However, it takes memory so, during rendering we recommend to disable preview by clicking on the eye icon.

Multilight tab / Emixer utility

Remember that in order to use this feature you have to previously activate it by the command –ml in studio command line, or in the command line render or in the MXCL render options (Enable multilight).



Once it is available, Emixer will list all the light sources of the scene, including sky (any of the available sky options in the current scene).

• Light slider: Controls the intensity of the light. It has a text box for introducing intensity numerically. • S: Means sole and will let the current light as the only light source, muting all the others. • M: Stands for mute and will switch off the current light source. • Max Frames: maximum number of frames in the Emixer timeline. • Video • Save sequence: Allows making a video with the animated emixer data. • Load EmiXer data: Loads an emixer file. • Save EmiXer data: Saves an emixer file.

Example of multilight edition from a single render. And transitions can be animated within MXCL.

Animated timeline.

→ Creating a Keyframe Grab the slider to set a keyframe at the desired time. Right click on the slider, set the keyframe and adjust lights values or turn them on and off.

→ Deleting a Keyframe Go to the keyframe you want to delete, you will notice it is a keyframe because the slider will turn orange.

Right click on slider and choose delete Keyframe. → Playback controls

• Go the beginning of the timeline.

• Play the sequence (preview) with this button or press spacebar.

• Pause the animation with this button or press spacebar .



Network Panel This panels control the network rendering features of Maxwell. For more information read the section related to network rendering. NETWORK RENDERING To easily understand how Maxwell distributes the job renders, take a look at the graph in Fig.1 The Manager gives an order for every Server, to send a software package with the process task. Once the Server has received the order, it starts rendering the solution. This solution is stored into a MXI file. Once the task has been finalized, the Manager tells the Server to wait to find another Server. When one of the remaining Servers has finished, the Manager sends the solution from the first Server to the second one to finish and in this way the two solutions are merged into a new one, which is a new MXI, and therefore allowing the first Server to receive another task.

ig. 1

o set up Maxwell Network Rendering, we need to configure our machines as Servers or the

o activate a machine as a Server, that is to take part of the render of the scene, we have to

o activate a machine as the Manager, we have to input in the command shell the “mxcl –

is strongly advised there be only one Manager activated.

he next step is to add a job into the Manager to be distributed in our net of Servers. To do this,

b

F TManager. Tinput in the command shell the command “mxcl –server”, This readies the machine to render. Tmanager”: This machine is responsible for distributing the render tasks. It Twe will activate in Maxwell Viewer in any Server. This is our graphic interface to launch and manage our renders. This is activated by input mxcl –d in the command. In the Networking tawe can observe several buttons.



Connect: Connect to the Manager to see the state of the jobs.

Options: Maxwell automatically searches the address of the Manager, but in case either it .

→ →can’t find it or you want to force it to another machine, you can redirect it using this dialog box

Add Job: →

• MXS File: We can find our scene to re er here.

• Command line Options: Show the render parameters values. Command line for

Priority: Priority for the job to render. The smaller the value, the greater the priority.

• Cooperative: This option is checked to ensure all Servers render the same image.

• Any available: Assign the job to all Servers activated.

nd

render. •



→ Remove Job: Deletes even an assigned job.

Stop Job: Stop the job in process.

Create Group: Create groups of Servers dedicated to one job exclusively. This means, a e

Ungroup: Ungroup Servers grouped.

Add: This option is very useful in case you want to distribute the render out of your local

ooperative Network rendering issues

here is a current limitation with cooperative network rendering. A Mac network has to be solely

Mac, cooperative Network rendering path names to shared folders on the network cannot

→ →number x of Servers is rendering a scene and other group rendering a different one. Select thdesired servers and group them. → →network (eg. the internet) C Tmade up of Mac processors and PCs only with other PCs. Incontain any spaces, for example “my documents” will not be valid. The same thing applies formachine names.



TUTORIALS _______________________________________________________________ In this section we will cover most of the topics for a basic workflow using Maxwell Studio with several tutorials. Tutorial 1: The Plane

1. Launch Maxwell Studio and import one or more objects (.lwo, .obj, .dxf, etc…) using the “import to scene” function (right click on the graphical viewport). In this case we have imported a plane.

2. Make a preview by using the menu in the left upper corner of the graphical viewport or (CTRL+P). You will get some warning messages since the objects have no materials assigned.



3. Assign any material by opening the material browser and dragging the material to the

object. The material will be assigned to the object automatically. Remember that the object must be selected previously.

4. Change the view using ALT + mouse and try some renders (CTRL + P for preview, CTRL + SHIFT + P for render). If you want to cancel the render, click on the viewport and wait for the render to finish the operation.

Additional tips:

- reduce the window to make faster previews - check that the material is properly assigned to the object in the object list - Try some variations of the sky, enable sun light, change sun position.



5. Edit the material by double-clicking it in the material list and reduce the “roughness”

property to create a more polished surface.



Tutorial 2: Basic Studio Environment One of the most basic rendering environments is probably a classical studio set. In this tutorial we will learn how to build a very easy one.

1. First of all we need a special ground object. The horizon of this ground is curved up to emulate the infinity of the environment. Click File / Open Scene and select the file \Tutorials\Studio Environment\studioground.mxs

2. Navigate (pan/zoom) around the perspective viewport and discover the shape of this typical studio ground. Next step would be bringing the lights and any simple plane would work for us. Now we want to add another object to the scene. So, click File / Import to Scene and select the file \Tutorials\Studio Environment\keylight.mxs



3. Now we have the most basic studio setup and you can preview the scene in any viewport perspective by pressing Ctrl + P from the desired angle of view. What we still don’t have is a camera and this is why the preview image comes darker than we expected.

4. In perspective viewport pan and zoom onto the ground plane, create camera (Ctrl+C) and set your camera shutter speed to 1/30 by typing 30 to the numeric field in the Camera Options panel. Now when you preview the camera view, you’ll see a very simple and empty studio environment.



5.

Studio Environment\pawn.mxs and position the camera manually to match the below

Currently our studio environment is working but it’s boring. So it would be good if we bring something to render on this clean ground. Click File / Import to Scene and select the file \Tutorials\

ote: Alternatively you can bring the same camera above by importing the camera.mxs

6. dd looking. We can enhance the lighting with a color backlight

to make it seem better.

N Now you can render and see the black pawn on the studio environment. But the scene is still very simple and o

7. Scene and select the file \Tutorials\

Studio Environment\backlight.mxs and render!

You can duplicate the keylight, reposition and define a new emitter material to achieve a backlight or you can simply click File / Import to



8. your own studio setups with more emitters, different

settings and different objects.

This final scene has been saved as \Tutorials\Studio Environment\studio_final.mxs and it’s ready to render. Explore



Tutorial 3: How to Make Plastic-Look Materials In common, there are 4 basic surface types in terms of their respond to light. They are metals, diffuses, dielectrics and plastics. Metals are in range of Mirror (roughness=0) through Diffuse (roughness=max), they are reflective materials at different roughness. Diffuse means a fully rough surface with a particular reflectance greater than zero (which gives the color of object). Dielectrics are transmittive materials in varying roughness. These three can easily be defined by one basic material BSDF.

METALS: Reflectives with varying roughness (e.g. MIRROR: White reflectives with zero roughness) DIFFUSES: Reflectives with maximum roughness. (above 80 or Lambert) (e.g WALL: Color reflectives with ~90 roughness depending the paint on them.) DIELECTRICS: Trasmittives with varying roughness. (e.g. GLASS: White reflectives with zero roughness and a proper Nd.)

Plastics are way complex about the concept of their appearence in real life. They basically have two surface properties at the same time. They have both a rough (mostly diffuse) surface which gives their color and a glossy (mostly zero roughness) surface which gives their specular reflectivity. It’s about surface microstructure. Thus, we need 2 basic material BSDF for achieving a plastic-look.

PLASTICS: Both rough and glossy reflective surfaces. (e.g. LEATHER: Color reflectives with lambert roughness and a glossy specular.)

Just as we refer to dielectrics when making water or glass for their response to light, independent of their mechanical properties, “Plastics” is a common term to describe both diffuse and specular kinds of surfaces. Generally speaking, nearly 90% of surfaces in real life have plastic behavior, so it will be good to know how we achieve them in Maxwell.

1. Click File / Open Scene and select the file \Tutorials\Plastics\sphere stage.mxs which will bring you a sphere on a typical studio setup. The sphere currently has no materials applied, so you will see a white ball when rendered which is still not a plastic yet.



2. Right click on Material List window and create a new material. Change the color of this material to 140, 0, 65 which is the example color of this tutorial. We now have a diffuse material which has no specular/glossy reflections to achieve a plastic-look yet. But the first BSDF is completed by this step.

3. Now right click on material layers window and select “Add Basic Layer” to create one more BSDF. Now it will be located at the bottom of the stack. Select it and set the reflectance color to 255, 255, 255 (white), uncheck Lambert and set roughness to 0. Thus, it becomes a perfect mirror which you can preview by temporarily setting the other layer’s weight to 0.



4. To achieve the plastic-look, all we need to do is blending these 2 BSDF layers with proper weight values. Before we make it in a hurry, we need to investigate some more steps to achieve the top quality. Most common shiny objects have a fresnel fall-off in their specular reflections which means the parts you see from the front reflects the environment less than their sides on glancing angles do. So, we need to set ND different than 1.0 to start having fresnel reflections and decrease the reflectance at 0 degree to emphasize this effect. Practically speaking, we’ll suggest you ND=1,5 and Reflectance at 0 degree = 95, 95, 95 (grey) which will blend the strength of reflectivity along the surface nicely. Now tweak the values of second BSDF with these values to have plastic reflections rather than a flat mirror.

5. Now preview your scene with each of the material layers you’ve created by setting their values 0 and 100 or 100 and 0 respectively. You will have a diffuse color ball and a dark reflective ball with these two consecutive renders you make.

BSDF Layer 1 BSDF Layer 2



6. Now all you need to do is setting proper weight values to blend these layers and there

you have the plastics! Here we have a table of different values demonstrating the possibilities you have only with playing weights and roughness. From left to right, you see the change in layer weights. From top to bottom you see the increase in roughness.

7. Mapping the reflectance of first BSDF (diffuse one) will also give you the chance to make more complicated materials like wood. You can also consider mapping both layers with a bump map, too.

Weights 70, 30 / Rough 20 Weights 70,30 / Rough 10 w/Bump=8



Tutorial 4: AGS (Architectural Glass Solution) Materials Included in the installation you will find several .mxm materials under Ateam’s Special library:

AGS_Standard.mxm

AGS_Black_25.mxm AGS_Black_50.mxm AGS_Black_75.mxm

AGS_Silver_25.mxm AGS_Silver_50.mxm AGS_Silver_75.mxm

AGS_Bronze_25.mxm AGS_Bronze_50.mxm AGS_Bronze_75.mxm

AGS materials have been specifically designed for use in architectural and auto glass applications, where the typical panel cross-section is less than 30mm, and complex refractive effects (caustics, dispersion, etc.) are not desired. As AGS materials do not possess the refractional attributes of common glass, they are generally unsuitable for such use. Also due to these property exclusions, AGS materials represent a much simpler calculation at render-time, clearing noise much faster than standard refractive glass materials. The anatomy of an AGS material is simple, yet leverages some of the more fringe capabilities of the Maxwell material system. All of these materials start with a simple dual-BSDF base, and where desired, are augmented with a third BSDF layer for tinting. For example, we’ll examine AGS_Silver_50.mxm:



The first (Refractive) layer is a fully-transmittive, non-reflective BSDF with a zero-refraction IOR (ND) of 1.00:

The second (Reflective) layer is a non-transmittive, variably-reflective BSDF with an IOR (ND) of 1.51:

The third (Tint) layer is a non-transmittive, color-biased reflective BSDF with an IOR (ND) of 20.00:

To better understand the mechanics at work in these layers, it is first necessary to review some of the finer points of the Maxwell implementation of IOR-Fresnel material properties, noting specifically the fact that the Nd parameter affects not only how light is refracted through a solid body, but how it is reflected as well. This is the key to understanding how to build an effective AGS material. Specifying an extremely low



ND (1.00) ensures that light will not be reflected, regardless of viewing angle. Conversely, an extremely high ND (20.00) will cause light to be reflected in a uniform manner, also regardless of viewing angle. The AGS materials start with a base layer where ND = 1.00 (no reflections), and transmittance = white [255,255,255] (all light is transmitted). This is effectively an invisible material, through which all light passes, and none is reflected. The second BSDF is functionally a mirror material, with a specifically defined fresnel fall-off curve. This is accomplished by specifying reflections of grey [64,64,64] @ 0° , and white [255,255,255] @ 90°. Using the natural ND for standard glass (1.51) provides an accurate fresnel fall-off curve for transition between the two reflections, the result of which is an accurate, view-angle-dependent reflectivity curve. These two base layers are then additively weighted together at 100:100, producing a simultaneous combination of transparency and view-angle-dependent reflectivity. In addition to these foundation layers, a third layer is optionally added to simulate tinted glass. This layer is a very simple color-biased mirror (ND 20.00) layer which can be easily manipulated by weighting to provide for an unlimited range of possible tinting requirements.



KEYBOARD SHORTCUTS _______________________________________________________________ File New Scene Crtl+N Open Ctrl+O Import Object to Scene Crtl+I Save Ctrl+S Naviagtion Rotate Alt + LMB Pan Alt + MMB Zoom Alt + RMB Local rotate Alt + Shift + LMB roll Alt + Shift + MMB Local zoom Alt + Shift + RMB In the camera view it would be Orbit, traveling and zoom Selection Select Object by frame Crtl+F Sect All Objects Crtl+A Hide Select Objects Crtl+H Unhide All Objects Crtl+J Expand polygon selection to connected region / Expand polygon selection + Collapse polygon selection - Invert polygon selection * Select + handles Q cycle selection modes groups, objects, triangles T Select (cycle) LMB also per window Add to selection Shift + LMB Remove from selection Ctrl + LMB empty selection Esc Set expand to facet selection mode F8 Set raycast for polygon selection mode F9 Set front-face polygons selection mode F10 Set paint polygon selection mode F11 Edit Create Camera Crtl+C Move W Rotate E Scale R Delete Del



Window Floating Window Ctrl + num Switch Window Alt + num 3d viewport “ + 1 Ortho (2D) view “ + 2 Material Editor “ + 3 Material list “ + 4 Object params “ + 5 Object list “ + 6 Camera params “ + 7 Camera list “ + 8 Sky Options “ + 9 render Options “ + 0 Display wind rose on/off Z cycle shading S Show/Hide sky K

Show/Hide Camera focus information (only in camera view) I

Automatically focus the target point of the camera F

In texture shading mode switch to see mapping coordinates or diffuse color P

Render Viewport preview Ctrl+P Viewport render Ctrl+Shift+P



IOR FILES _______________________________________________________________ A full IOR file (or Complex IOR file) stores the index of refraction (N) and absorption or extinction coefficient (K) for each wavelength. It is an ASCII file that follows this specification:

<spectral_unit=1> <spectral_range> <spectral_range> <number_of_intervals> <N> <K> <N> <K> . . .

This is an example:

1 .5 6 110 1.205 15.5 1.034 14.14438 .896 13 .78525 12.03063 .696 11.2 .621563 10.4575 .559 9.81 .503063 9.203125 .454 8.77 .410188 8.757501 .372 8.77 .339375 8.40375 .312 7.93 .2905 7.485001 .272 7.07 .253125 6.753125 .236 6.47 .222125 6.168125 .21 5.88 .198125 5.63125 .188 5.39 .181375 5.125813 .176 4.86 .1695 4.610188 .164 4.357 .160875 4.087687 .16 3.8 .161 3.445812 .166 3.15 .17775 3.07 .194 3.06 .212375 3.015 .236 2.97 . . . The custom IOR file just ignores the second value (absorption).



ACKNOWLEDGMENTS _______________________________________________________________ People who contributed to this document: Maxwell A-Team Next Limit Team Cover Artwork Hervé Staff - [email protected]


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THE LIGHT SIMULATOR

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