autodesk® alias® design for the absolute...

Autodesk® Alias® Design For the Absolute Beginner Jamie Gilchrist – Autodesk, Inc. Jay Tedeschi – Autodesk, Inc.

MA5242-L

Are you new to Autodesk® Alias® Design? Did you recently acquire one of the new Ultimate Suites that includes Alias Design and you are not quite sure what to do with it? Come to this hands-on lab and get some drive time with Autodesk Alias Design 2012 and start to leverage one of the most powerful surface modeling tools for industrial designers into your product design and development workflows. Get some hands-on basics of NURBS-based curve and surface modeling and understand the power and speed at which you can model your ideas in Autodesk Alias Design.

Learning Objectives At the end of this class, you will be able to:

• Navigate the Alias user interface easily • Define proper file setup, including project folders, units, and tolerances • Achieve some basic modeling tasks using primitives and NURBS-based curves and surfaces • Leverage some of the more powerful curve and surface editing and analysis tools inside of Alias Design

About the Speaker Jamie has a broad range of experience ranging from designer to engineer to project manager. He has been involved with projects from a purely conceptual nature to implementing design for manufacturing. Jamie has acted as liaison between vendors and clients to ensure that the communication and flow of development data is exchanged in a timely and efficient manner. He has a broad knowledge of rapid prototyping processes, and knows what it takes to get a product from idea to prototype to production. His main strength is in the implementation from sketch to computer data in both 2D and 3D. [email protected]

Autodesk® Alias® Design For the Absolute Beginner

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Getting Started

The Alias User Interface

Single View vs. Multi View

Optimal Alias working environment in a single view


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Alias working environment in multi view. Notice that your active window or view will be framed by a white highlight.

When working in a 4 window environment you can control the behavior of the model in the three orthographic windows to move, zoom and pan synchronized or independently by enabling or disabling Window Sync. WindowDisplay>Window Sync


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To change back to the Single or Perspective view Layouts>Perspective (F8)

While Alias is incredibly customizable I am going to suggest we stay with primarily default settings for the time being until you become more familiar with the workflows and have a better understanding of how you work within the Alias environment.

Let’s take a look at the UI elements that we are going to be concerned with for the rest of this class.


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Palettes, Shelves, Control Panel and Object Lister

What are these elements on the screen? Let’s break this down as simply as possible.

• Palette- this is where all your paint, curve, surface and mesh creation and edit tools reside, as well as locators (dimensioning, measuring), evaluate (analysis) and construction tools (planes, points).

• Shelves- a sub-set of the Palette. The default shelf set is what we will focus on through out this class as it has already been set up and organized to address 95% of the typical tasks you will commonly perform modeling within Alias Design.

• Control Panel-gives you quick access to “control” your curves and surfaces, i.e. toggling control vertices (CV’s), changing degree and span structure and visual analysis states.

• Object Lister-this is your layer structure, it offers a lot more functionality that is beyond the scope of this class.


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Getting back to our “optimal” working window

Make sure the following are set: Long Menus are on


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Set your Palette and Shelf Layout

Note: when you click on the Option Box on the Palette/Shelves Layout menu a dialog box opens. Tip: This is the typical behavior of all tools that have the option box, whether in a menu item or a tool icon.

When you “Save” in the option box this will retain these settings for the next time you launch Alias, if you only hit “Go” the settings will only retain for the current working session.


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Marking Menus & Navigation

Marking Menus Marking Menus are a key component to the speed and flexibility of Alias. The Main difference between having a contextual menu and marking menus is the way in which the marking menus are organized. Keep in mind that marking menus can be customized to address the way you work, however, I would urge you to shy away from customization until you are comfortable using the marking menus and really understanding the way you work in Alias as you become more proficient.

In order to access the marking menus simultaneously hold Shift and Ctrl along with one of the three buttons on the mouse

Let’s look at the logical structure of how the Marking Menus are set up.

Left Mouse Button: Selection Tools


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Middle Mouse Button: Transform Tools

Right Mouse Button: Viewing Control

It takes time to get used to working this way, but remember that once you do you have incredibly fast access to 30 frequently used tools right at your point of work.


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Navigation Navigation in Alias is similar to the marking menus activated by two clutch keys. Holding Shift and Alt while pressing one of the three mouse buttons and each mouse button activates a different camera control.

Tumble

Track (Pan)


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Zoom

If you are used to working in Inventor or AutoCAD you will already be familiar with the view cube and can use it to quickly change your camera view.

Tip: if you get lost in navigating your model, i.e. you’re zoomed too far in or out or away from the geometry of your model you can quickly get back to your model in a number ways:

1. Use the home Icon on the view cube

2. Use The Look at Button on the viewing panel.

3. Use the Look At hot Key:


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File Setup This is a critical step in starting to work with Alias and modeling in the Alias environment. Understanding what the downstream uses of what you’re creating will determine a number of things you need to consider such as: tolerance, units and orientation. We will cover these shortly, but it is important to keep the following in mind.

Alias is: 1. a tolerance modeling application 2. a Z-up modeling application (most solid modelers are Y-up) 3. only going to do what you tell it to

Units & Tolerances

These settings are controlled under menu item Preferences>Construction Options.

There are a number of construction options presets that will be appropriate for most of the modelling and downstream consumers of what you’ll be creating. For this class we will use the Inventor construction option preset.

Note: Construction Options need to be set prior to building any geometry. If you start modeling in a tolerance that is too loose all the geometry will need to be to re built in the correct tolerance set-up. You can change tolerance settings mid stream, but everything you’ve built up to that point of change will remain in the previous setting and will likely have to be rebuilt. You will save yourself lots of time and downstream headaches by modeling in the correct tolerance from the start.


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Tip: if you need to set your own tolerances or units copy one of the Construction Presets and make the appropriate adjustment for your needs. Example: copy the Inventor preset and change the Fitting, Continuity and Curve on Surface/Trim to all be at 0.001 mm and rename the preset to “Inventor tight”. You can create your own from scratch, but starting with an existing preset only requires a few changes to get the exact tolerance scheme you require.


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Tip: now that you have your Alias environment dialed you can save the user preferences so that these settings remain persistent. Preferences>User Preferences>Save Preference Set. Preferences have file extension .aps (Alias Preference Set) and contain the following components:

• Shelves • Marking Menus • User Options • Colors • General Preferences • Hotkeys • Workflows & Menus • Construction Options


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Let’s Start Modeling

Setting the Project If you’re familiar with Inventor and using project files, Alias keeps all your files organized too, but uses a common systems directory rather than a dedicated “project file”. Let’s open the file and set the project.

Menu>File>Open

When the dialog window opens you can set your working project: this is where the .wire file will be saved along with any other project related items including: reference files, pix, shaders, options, etc. In the Open dialog find the folder MA5242-L Datasets and und the Project pull-down choose the “Set Current”, this will set the Wire folder as the active directory where your files are saved and continue to be your working directory until you change to a different one.


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Open the file MA5242-L_Display.wire

Curves: Keypoint & CV Keypoint Curves are akin to the types of curves you’re likely to be familiar with in a typical solid modeling package; they have point-by-point or numeric entry, there is a dimensional value to them and they are most efficient for quickly laying out dimensional curves.

CV and Edit Point Curves on the other hand are driven by the underlying math. They are dimensional, but not in the way a radius is, for example, in a 2D sketch. (go the Alias wikihelp page if you want to learn a more about the mathematical representation of curves used in Alias).

For this Exercise we are going to cover: • Entering and editing Keypoint Curves • Using Curve Snaps • Entering CV and Edit Point Curves • Using the Information Window • Using the Control Panel

When you first open our working file you’ll see that the curve layout for our monitor is incomplete and we need to finish the layout before we begin building surfaces to complete the model.


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Our First Curve we are going to enter we will use the Keypoint curve >Line and we want to snap to the end points already existing on the left side of the screen.

To get accurate snapping there are two ways we can do this (as is typical in Alias, there are usually more than a single method for achieving the results you are looking for). The fastest method is to use the keyboard short cuts to snap and since your fingers are already at the clutch keys to navigate and access the marking menus, guess what? The control and option keys are what you need.

Hold the control key and click near the end point at the bottom left, a white hash mark will indicate the first point of your line. Before you release the mouse button


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Also notice right of the Promptline that the Point Snap Icon is highlighted as you are snapping. Snap Near the end point of the line above

Tip: the Snap icons are also switches. You can select any one at a given time to be the dominant snapping behavior, however, the key toggles will override your selection. E.g. if you have Point Snap selected and are using the Curve Snap key combination, you will snap to curves and not points.


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Let’s edit that curve using the Information Window, with the curve still your active selection, bring up the Information Window using the marking menu> Hint: control+shift+rmb straight up.

With the Information Window now open we can edit the attributes of this curve, namely the Length, but we need to know what the length of the other curve is to match it.


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Remember when we said Alias will only do what you tell it to? Okay, since we opened the Information Window while the curve we just created is active, we are still in the curve creation tool. We need to go to an appropriate selection tool before we start clicking around to select the curve we want to match to. So go to your selection marking menu and select curves. Hint: control+shift+lmb lower right. And use the middle mouse button to select. This will “Add” this curve to your selection. Now in the information window, match the length of the curve you just created to the existing one. Type or copy and paste and press enter.

Go ahead and add the top line to finish out the front profile on your own.


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Finish the Back Curve Profile using the Edit Point Curve and Snap to the three points on the backside of our model.

Tip: you can also access the tool by right clicking on the Shelf name and access all the tools available in that shelf. As you get to be more of a power user you will likely find this is a much faster way of accessing your tools.


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Now we are going to look at the information and controlling our curves in the Control Panel. As you can see the control panel is giving us some immediate feedback on the curve we just created. We know that it’s a 3-degree 2-span curve. We can toggle the CV/Hull, Edit Points, Blend Points (not covered in this class) and Isoparm UV display (surfaces). We can use this information to quickly make changes to our curve, in this case and surfaces too.

Let’s go ahead and change the number of spans to one and keep this a 3-dgree curve, now before you accept this change notice in the Promptline that you are getting a deviation based on this change.


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It’s not clear where, but a maximum deviation of 0.0366mm is happening on that curve. For our base layout curves this will be acceptable, but know that you may find some situations where this is unacceptable.

Click on the Accept button to accept these changes.

Tip: you can also just hit the Spacebar to accept.

Tip: a best practice for controlling your surfaces is to make sure the underlying curves (if there are any) is as simple as possible. More spans in the curve mean a “heavier” surface that may be difficult to really achieve your design intent.

The surface on the left was built using curves with “light” parameterization (i.e. the underlying curves were 3-degree and single span) the surface on the right was built with curves that had “heavy” parameterization (i.e. the curves were 3-degree, but had 9-spans each) resulting in a surface that can prove to be troublesome down the road.


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As was said earlier, there are number of ways to achieve the same results in Alias and naturally we tend to gravitate to the way we learned, were taught or know that’s the fastest way, don’t be afraid to try something different.

This example shows what looks like 3 identical curves, but upon close inspection we can see that they are slightly different and any resultant surface will result in slightly different looking surfaces.


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Primitives and Positioning Often times in doing design exploration it’s important to do block studies to better understand volumes and proportions the surface Primitive tools give you the basic means of quickly creating and editing 3D forms. Remember this is not high accuracy modeling at this point.

For this Exercise we are going to cover: • Using the Object Lister • Creating and Editing Primitive Forms • Scaling and Moving Objects • Quick Modeling to Illustrations

Let’s start by turning on the Canvas Underlay layer. Hint: click on the box with the line through it at the bottom of the Object Lister. Now make the Primitives layer the active layer by clicking on the layer name. This will make all the objects you create on the “primitives” layer.

In the Surface Tools shelf go to the Primitives>Cube. Type in the number 0 and hit enter. This will place a cube centered around 0, 0, 0 of the stage or model space


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Now use the manipulators to move the new Primitive Object into location. Use the View Cube to toggle between front and side views to quickly locate and scale the object. This can be done in a few quick steps as long as you don’t de-select the original object or click in the active window, which will add an additional cube (Remember Alias stays in a tool until you change it).


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Tip: if the manipulators are no longer available, i.e. you deselected or inadvertently created a second cube, you can still move and scale the original cube with a combination of the Move and Non-Proportional Scale marking menus. Hint: control+shift+mmb straight up or lower left.

Lastly we want to we want to mimic the curvature on the back, quickly. With the Cube selected, turn on the Cv/Hull in the Control Panel. Tip: you can also turn on the controls using the marking menu control+shift+rmb lower right.

Select the four center CVs on the back surface. Hint: use your marking menu>select CV and middle mouse to “add” select.


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Then move the selected CV’s in the Y orientation to closely match the shape of the illustration. Use the View Cube to go to a side view to match the surface. Use the marking menu move command. Hint: control+shift+mmb straight up then use the middle mouse button to constrain the movement in the Y-orientation.

Tip: when moving anything (CV’s, objects, curves or surfaces) the left, middle and right mouse buttons constrain the movement to X, Y and Z respectively when in perspective view. This behavior changes slightly when in an orthographic view as the left mouse button allows for free movement.

Alternative Method: you can use the Transform CV in the Control Panel. With this selected you can press the Sapacebar and activate the Hot spot tools and choose CV’s or Hulls and move your selection in X,Y,Z or NUV (normal to surface). Again showing the “many ways” methodology available within Alias.


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Curved Based and Direct Modeling Now we are going to look at the bulk of accurate modeling using Alias. We are going to concentrate on the main form of the monitor and build an accurate surface model.

For this Exercise we are going to cover: • Automated Surface Creation • Blend Surfaces and Continuity • Dealing with Complex Corner Conditions

Next steps we’re going to build the base surfaces and begin to detail out the design. First step is to make the layer “Multi-Surface Draft” the active layer. Also make sure you have the Canvas layer visible, but not the active layer. Under your Surface Tools shelf find the Multi-surface draft tool. Hint: you can right click in the shelf name and find it under “Surfaces”. Select the four curves that define the base profile of the Monitor. Switch to a side view so you can see how deep to make the surface.

Make sure the Auto Recalc. Option is selected, this will give you real time feedback of what you are building. As you can see there are quite a few controls here, what’s important to understand is you have both on screen interactive controls as well as the ability to enter numeric values too. Now that is done, you can hit the Next button, which will keep you in the tool with the control dialog open, or you can Select Nothing which will keep the tool active, but close the control dialog. Hint: control+shift+rmb straight up. We next want to blend the corners.


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Activate the Layer Continuity, and take a look at what is happening at a mathematical level on the curves and a visual level on the surface. From the far left we go Positional, Tangent and finally Curvature continuities.

Mathematically the difference between tangent and curvature is the rate of change which shows really well in the curvature comb on the curves. The difference between tangent and curvature that designers most typically care about is the perceived quality of the surface of the product. This is especially true when the final finish material is highly reflective and not masked by texture.


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So let’s build some blends. Go to the surface filet tool.

or

Open the Surface Filet Control window and start selecting surfaces. You have to select one at a time and accept each selection. Also make sure that the Auto Recalc. Option is selected as well. Make sure the Continuity Check is enabled and go to a front view. For this corner adjust the size of the filet to closely match the front view of our illustration.


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Finish the remaining corners. Tip: notice that the newly created surface boundaries are green? That means there is construction history and you can go back into the command and make changes as you’re tweaking your design. Use the Query Edit History or marking menu-mmb to the right. Now we get to deal with the back surface; the not-so-simple back surface. Remember how we did the bulging on the back on the primitives? We are going to do something very similar, but first we need to adjust the main surface so it is closing off the entire rear - top and bottom.


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For this we will use a combination of moving the selected CVs in a constrained direction and snapping to the surface edge. The steps are:

1. Select the CV in the top row. Use your marking menu. 2. Move them constrained to the Z-axis. Engage the move command using your marking

menu. 3. Snapping to the top edge of the Draft Surface we built earlier

Note: if you attempt to move the CV while in a perspective view and snap to a curve, all your selected CVs will attempt to converge at a single snap point, so be sure to switch to an orthographic view before attempting this.

Do this for the bottom edge too and repeat the process we did in the primitives section where we bulged out the back to meet our design intent. You final surface should look something like this:


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Now we need to deal with finishing this corner with a patch surface to blend out to the edge of the adjacent surfaces.

There are a few different ways to approach this, they fundamentally begin the same, but the way you build the surface and the results you get will vary. Here we will show you one way, but the file has a second way shown. The first thing we need to do is trim out the area where we want to build our patch surface. Activate the Back Corner layer (if you still have the canvas layer or any others visible, toggle them off.) and you’ll see a set of curves already exist to project as our trim area. In your Surface Tools Shelf select the Project Curves tool and open the Project Control Window.


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We want the following settings

Select the surface and Accept, now select the curves and Project.. Now trim the surface and select the area to keep or discard.


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This is the result you should have.

We are going to take a quick look at a two options here:

1. A Square Surface 2. A Multi Generation Rail Surface.


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First Up, Square Surface. Open the Square Control window and select all four edges of our trimmed surface as shown Set edges one and three with Tangent continuity and edge 2 with Curvature continuity.

This looks pretty good, but if you look at the Control Panel you’ll see this is a pretty heavy surface (like our earlier example of heavy surfaces) it has 23 spans in one direction, not ideal, plus if you look under one of the diagnostic shading modes you’ll quickly see this is not a very good surface. See the kink in there?


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One option we can try is checking the rebuild boxes in the Square Control Window and instantly we see a better CV/Hull layout. This is because Alias is virtually rebuilding the trimmed surfaces to a much more efficient parameterization Yielding a better quality surface.

It’s better, but not really what we want.


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Let’s try the Multi-Generation Rail Surface. Open the Birail II+ Control box and select the three generation curves and hit the Go button. Hint: hit the Spacebar.

Then select the two rail curves. Set the Generation edges to Tangent continuity and Rail 1 to Curvature. The results again not too bad and the number of spans is at 12..


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As you can see, a much better result with the Zebra Stripe; and just by having that extra bit of control with the additional curve in the middle of the surface.

Here is the result of a third method that was all direct modeled to achieve the result of a 3x5 degree surface with 1x1 spans. (we will cover this if time permits, otherwise look for a video on the AutodeskDesign youtube channel).


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We have the rest of the finished surfaces built and with everything you’ve learned today you should be able to easily finish the rest of the model. Hint: the screen projected? Learn more here: http://wikihelp.autodesk.com/Alias/enu/2012/Help/0000-Alias_He0/0726-Referenc726/1045-Menus1045/1222-Canvas_m1222/1228-Canvas__1228


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Further Alias Learning Resources

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