essence theface modeling and texturing

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THE FACE

PAUL FEDOR • PETER LEVIUS

HONG SUCK SUH • MATT HARTLE

MARK SNOSWELL • STEVEN STAHLBERG

EDITED BY • DANIEL WADE

™C R E A T I V E



contributing artists

PAUL FEDOR

TEXTURING

Paul Fedor recently worked with Sony’sresearch and development team where he

teamed up with Academy Award winning Post

Supervisor Nick Brooks, and Mathew Lamb

PHD as a consulting team on cinematics and

pipelines. His focus was pushing the

standards for next generation characters for

the launch of PlayStation 3 wi th his work and

research centered on perfecting a photo-real

digital character pipeline.

™C R E A T I V E

Peter Levius started his creative career asa 3D character artist for a gaming company.

After a series of game projects fell victim

to cancel lat ion Peter tur ned to ano the r

passion of his which was the collection of

photo-reference. With Richard Polak, Peter

created 3D.SK, a web site completely focused

on photo reference for the creation and

texturing of 3D characters for movies and

video games.

By the time Hong was 15 he was studyingprogramming and developing his own drawing

software. He decided to study CG in the

United States where he majored in Computer

Art at the Academy of Art University (AAU).

His first job was at WildBrain before joining

ILM as a Creature Modeler. Hong’s next step

was Character Lead of Cinematic Group

in SCEA where he currently works on

PlayStation 3 cinematics.

Peter levius

PHOTOGRAPHY hong suck suh

MODELING

Each ESSENCE book brings together between six and ten of the world’s most talented3D artists in their area of expertise. Working as a team, the artists will work on each piece in the 3D character puzzle showing you how characters are created ina production environment for the most efficiency and best results.

ESSENCE The Face4



Dr Mark Snoswell is President of TheCGSociety and founder of Ballistic Media.

His diverse range of experiences include:

development of Absolute Character Tools

(www.cgCharacter.com); development of The

Ultimate Human Model set; film production

work for Disney and Warner Brothers;

production work for National Geographic; and

teach ing graphic design, 3ds Max and Painter.

Mark’s background also includes multimedia

design and a career in biotechnology R&D.

mark snoswell

MODELING, RENDERING, TEXTURINGsteven stahlberg

EYE MODELING

Steven Stahlberg co-founded Optidigit andAndroidBlues, the virtual talent studio. He is

a 2D and 3D artist, illustrator, art director,

and animator. After completing his art studies

in Sweden and Australia Steven worked ten

years as a freelance illustrator for leading

advertising agencies and publications in

Europe and Asia. Steven is a co-author of

d’artiste Character Modeling and an online

instructor for CGWorkshops.

creative ESSENCE: THE FACE

the Artists

Matt Hartle is 3D Director at Deva Studios andprior to that was the 3D Department at BLT and

Associates. He has worked on movie trailers

including: ‘Babel’; ‘The Prestige’; ‘Pirates of the

Caribbean 3’; ‘Charlotte’s Web’; and ‘X-Men 2’.

He has also done visual effects in films such as:

‘Van Helsing’; ‘Casanova’; and ‘Scorched’.

Matt has taught at institutes for animation and

visual effects, including: the Gnomon School of

Visual Effects; The Art Institute in Santa Monica;

and the Academy of Art in San Francisco.

matt hartle

RENDERING

ESSENCE The Face 5



™C R E A T I V E

photography

Pretty in pixelsPhotographingCG reference

10

modeling

About faceModeling thehuman head

22

TEXTURING

Perfect headsUV Mapping

32

TEXTURING

Perfect fitModels and texturesfrom photographs

38

TEXTURING

Skin deepReal-time map making

48

TEXTURING

Making a startBuilding up maps

56

TEXTURING

Pre-HairCreating abaldness map

68

TEXTURING

Time for updatesRefining the details

76

TEXTURING

Getting the bumpBump-mapping

84

ESSENCE The Face6



creative ESSENCE: THE FACE

CONTENTS

TEXTURING

Shiny happy pixelsSpecular highlights

88

modeling/

TEXTURING

Eye of the beholderSimulating human eyes

92

modeling

A head aboveParametrichead creation

100

rendering

Real skinSub-surface scattering

108

rendering

Under the skinPoor man’s SSS

116

rendering

Lights, camera, renderLighting andrendering Monika

124

TEXTURING

Cosmetics in pixelsSimulating makeup

132

TEXTURING

Bruising & scarringSimulating tissuedamage

142

TEXTURING

Aging MonikaPainting in

the years

152

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10 ESSENCE The Face

PRETTY IN PIXELSPHOTOGRAPHING FOR CG REFERENCE

Lights, makeup, lights, camera, action

Our most popular reference website in the3D.SK family of sites is Female Anatomyfor Artists. It’s fairly easy to guess why ashuman anatomy is the foundation for most types of fantasy il lustration or 3D ar tworks.The website is focused on figure drawing,anatomy study and posing/rigging of3D models. For our regular photo shoots,we typically shoot full-body shots of models

in various poses from classical figuredrawing poses, action fighting poses,moving poses, and requested poses.We prefer to shoot the models withhard shadows.

The Monika photo shoot was for 3D.SK, so the brief was a little different. The assignmentwas to create reference shots for a glamour-style magazine cover. Adding makeup to themix provided a big challenge to the shootso we brought in a professional makeupartist, Gabriela Kleinova, who was able to do some great work.

A photo shoot is a team effort andwe had the full 3D.SK team involvedincluding Veronika Jaskova AKA Kristin

(project manager for the anatomy websites andmanager of models and photo shoots); TomasBabinec (project manager for Environment Texturesand 3D.SK); and Jiri Matula (photographer).

Diffuse Lighting: Main key light (1000W) ispositioned straight in front of the model.We use a soft box (150cm) to diffuse the light.There are also lights on the sides of the model.

One additional light is used to lighten up the background as this helps with post-production. For details such as the head,eyes and ears, we also use reflector boards.Contrast Lighting: Main key light (1000W) ispositioned on the side of the model and thereis another fill light in front of the model. Thiscreates very good shape definition, which isvery useful for sculptors, painters and,figure drawing students.

3D.SK has expanded in many directionswith several specialty sites including:Female Anatomy (female-anatomy-for-artist.com); Human Anatomy (human-

anatomy-for-artist.com); EnvironmentTextures (environment-textures.com);and 3D Tutorials (3dtutorials.sk).

10 ESSENCE The Face

Peter

Levius



ESSENCE The



22 ESSENCE The Face

Modeling from photo reference

The first thing to know about modeling the human head is what makes a facelook different whether it’s age, gender orrace. It’s then a matter of concentrating oncatching all of the unique features of thereference or what you want the model tolook like. It’s also important to remember that no mode l will look right without someknowledge of human anatomy.

Creating a human head is pretty simple, but the hardest par t is matching and addingcharacteristics to the model. Small changescan make the model look completelydifferent, and sometimes it’s hard to definewhat makes the model look odd or right.

When I do my personal work, it takes anendless amount of time to finish a singlehead model. It will always look differentfrom day to day, and I’ll constantly see things that need to be f ixed . This is because the creative process is dependant on mymood and environment. Usually, I’ll watch

a movie or listen to music which is related to thecharacter while I’m modeling. This keeps my moodeven and that helps me to pull out characteristicsfrom the model. It usually takes me less than fivehours to complete the head modeling.

Another way to simplify the modeling processfor me was to create my own tools. A coupleof years ago, I created a tool which helps me

generate human characters in order to speedup my modeling process.The tool generatesUVs, multiple levels of geometries, and addsfine details to the model automatically. Eachlevel of detail also contains around onehundred facial blend shapes. This helps mebuild basic features of the human head witha couple of clicks and lets me concentratemore on giving life to the model. The tool is not only for mode ling, so it cancut down production time on texturingand animation work as well. This allows the tex ture ar tis ts and animators toconcentrate more on the creative sideof their craft.

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about facemodeling the human head

HONG

SUCK SUH



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32 ESSENCE The Face

PERFECT HEADSUV MAPPING

Perfect generic models and UV mapping

There are five main stages I recommend forcreating a photo-real, textured 3D model.They are: generic modeling; photography;UV mapping; detailed model fitting; and texture generation. You can group the foursteps into two stages: generic modeling/UVmapping and detailed photography/texturebaking/model refinement. The first two steps,generic modeling and UV mapping, are basic

characteristics of a head model and areindependent of any actual textures or detailedface morphology. This is what we will coverin this chapter. We will look at combining thephotography, model refinement, and texturebaking in the next chapter.

Generic modeling and UV mapping sharemany of the same goals: use quads foroptimal subdivision; have smooth edge lines that follow the contours of the face; haveeven shaped and sized quads (maximumrelaxation within the surface shape); and havedetail where it is needed around the eyesand mouth. Ideally, your head shape and

mapping are based on the average humanmean shape so you can later plug it into aparametric head program to change its shape to any human head.

UV mapping involves generating mappingcoordinates for each 3D vertex. As the 3Dvertices have XYZ coordinates, the texture’scoordinates are named UVW. While it ispossible to paint totally in 3D and ignore alldetails of UV mapping, this is very inefficient.We need to pay the same attention to thequality of the UVW mapping as we did to the XYZ modeling.

All 3D models are broken down into triangles at render time. This is because a triangle is a minimum definitionof a plane area. A triangle in 3D space can always beviewed flat-on for the purpose of placing a 2D textureon it. It’s possible to convert any 3D shape, no matterhow complex, into a flat shape by taking all the triangles and laying them out within a rectangle.So, no matter how complex a 3D surface is wecan always cut up our texture into lots of separate

triangles and pack these into a rectangular mapfor texturing. This will always work, but it’smessy, wasteful of space, and creates lots of technical problems blending the edges of all those triangular texture pieces.

The goal is to come up with a minimumstretch, maximum connectivity mapping from2D (UVW) space to 3D (XYZ) space. Ideally, the 3D mesh and 2D UV mesh have thesame topology. There are a number of ways to approach this problem, but one of themost successful ways is pelt mapping.In this procedure, you think of the 3Dmodel as a skin you want to cut open and

stretch—like real-world pelting.

Finally, you want to consider the use of2D texture and how it maps to your 3Dmodel. As humans, we focus on thefront of the face—the triangle between the eyes and mouth in particular. Your UVmapping should reflect this natural focusand give preference to this region.

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mark

snoswell



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38 ESSENCE The Face

PERFECT FITMODELS AND MAPS FROM PHOTOGRAPHS

Model fitting and projection mapping

With a good generic model and UV mapping,we can move on to combining the photographsinto a single texture. First, we need to alter ourgeneric model to match the photographs. HongSuck Suh and Paul Fedor show the best practicefor doing this in the traditional way: modelingby hand with the photographs as a referenceand then morphing the photographs to fit aplane projection onto the model. I will show

an alternative approach here, and highlightadvances that can be achieved with someDirectX shader tools that I have developed forblending multiple photographs onto one model.

In the first step, I use FaceGen to generate afitted head model using the front and two sidephotographs. I do this on the 2K version of themodel from which I know all changes can beeasily propagated to the 9K and 36K models.FaceGen is a parametric head modeler fromSingular Inversions that we will take a close lookat in the chapter on ‘Parametric head modeling’.

There are several approaches to combining

photographs onto a modeled head, but allof them share one common element—theprojecting of the photographs onto the 3Dhead using one UV (projection) mapping perprojection and rendering out (called unwrappingor baking) the projected photograph to thedesired (unified) UV mapping. You repeat this with photographs from many anglesand combine all the unwrapped photographs.There are a number of approaches to the coreproblem of accurately projecting, warping andcombining the source photographs:

1. You can leave the model as is and warp thephotographs in Photoshop to fit the projected

mapping. You can also do this in your 3Dapplication where you’ll get the benefits offloating-point color representations and a richerset of 2D warping tools than in Photoshop.

2. You can temporarily alter the model to fit eachprojected photograph (this does not alter the target UVmapping), render out the unwrapped photographs andcombine them all in 2D and apply them to your original3D head. This approach has the benefits of doingeverything in the floating-point color space in your3D software. An even bigger benefit is that thereis a far richer set of tools for warping a 3D model than you can possibly get in any 2D software

like Photoshop.

3. You can alter your 3D head model to fit all ofyour projected photographs, unwrap and combineyour textures which you then apply to the refined3D model. Your model now fits the photographsas precisely as possible and you get the bestquality texture possible. This is the best overallapproach, but it requires a very good fit of theprojected photographs to the model.

Whichever method you use, you will have to color-match the individual unwrappedphotographs. This has to be done by handand in small pieces—even with consistent

lighting there are color variations. Therelative color and luminance will varyacross each photograph as a functionof the diffuse, sub-surface and specularproperties of the skin.

I will show solutions to both the color-matching and accurate projectionproblems which make the third approachboth the easiest and highest quality. For this chapter, I developed a DirectX shader that was meant as a tool for displayingmultiple projected maps concurrently on the one model. The shader developmentwent so well that I was able to add

an automatic tone-mapping function thatdoes a perfect blend of all the projectedphotographs in real-time and at every pixel.As you’ll see the results are astounding!

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snoswell



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48 ESSENCE The Face

SKIN DEEPREAL-TIME MAP MAKING

All the maps

Not so many years ago (OK, 15 years or more),you used a single texture map for materials. Thesame map was used for diffuse color and bumpmapping—that was all the renderers copedwith. Now, the average graphics card is capableof rendering far more complicated materials than most designers can create. So, although things like sub-surface scattering and pre-computed transfer functions are a walk in the

park for graphics cards, many designers are stillmaking materials for last millennia’s hardware.

We are on the verge of being able to docompletely physically correct shading for allmaterials. Along the way, the demands fordefining materials and their interactions withlight have risen sharply. This is particularly sofor skin which is perhaps the most complex,and changeable, of all materials that we willever want to render.

It’s not just photo-authenticity that we want toachieve anymore. It’s a degree of believability that a material is real and that it works in any

environment we care to put it in. This meansgetting the light model correct. The greatrendering advances over the past few yearshave come mostly from improved lightingand interaction of light with materials. For skin this means understanding and reproducing translucency—sub sur face scat teri ngof light.

We have a chapter devoted to skin structureand sub-surface scattering, so I won’t gointo detail of how to re-create the skin here.However, all of the problems that translucencygive for rendering turn into benefits whenextracting textures from photographs of skin.

This is because so much of the incident lightenters the skin. Once in the skin, there is adramatic difference in adsorption of differentwavelengths. The shorter the wavelength,

the greater the attenuation. So, the blue light hardly getsin into the skin at all, green gets in further and the redlight penetrates deeply.

During the development of the map blending DirectXshaders it became clear that I could add automaticgeneration of a lot of new maps that characterizesub-surface scattering in skin. It also becamepossible to generate bump and specular maps

better than was previously possible. This is awork in progress, but the results are already aquantum leap forward.

Very shortly these tools will allow you topreview your final material (with full sub-surface scattering if you want) in real- time—they will be generated and applied inreal-time. When you like the final resultantmaterial, you will be able to hit one button to“bake” the entire material—maps and all.

As the DirectX shader tools I have developedwill become widely available to the digitalartists community through our CGSociety

(www.CGSociety.org), I have taken time toshow what they are doing here in somedetail. Being DirectX-based, they will alsowork everywhere—in every 3D softwarepackage and even in games and otherstandalone environments.

As you look at the illustrations here,remember that in most cases whenI talk about the maps I will be showing themap on the 3D model surface rather thanas an unwrapped map. The map will notbe rendered with lighting—just applied to the 3D surface. With all the map blendingand tweaking being done in real-time, you

get used to looking at the maps like thisrather than flattened out. Of course, youcan also tell the render to show you themaps flattened out in real-time.

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snoswell



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56 ESSENCE The Face

MAKING A STARTBUILDING UP MAPS

What is 4K, and why 4K?

Nyquist–Shannon sampling theoremsays to pull off photo-real resolutionyou need to have double the pixel ratio to generate the necessary anti-aliasing.If you’re an artist and not a mathematician,simply take a 2K (2,048 x 2,048 pixel)face map and zoom in on it—you’ll seepixelization of the character’s close-up.To avoid pixelization in close-ups you really

need 4K maps (4,096 pixels x 4,096 pixels).Which means if a human is seven heads tall, you are looking at least 28K wor th of texture maps. The industry is in for a bigwake up call—there is nothing that drivesme crazier than the bad airbrushed look ofsome CG models.

Shrinking resolution is a basic rule in print.When doing a book cover illustration youpaint four times larger at screen resolution(72dpi) and change it to print resolution(300dpi) to fit on the cover. You don’tcreate extra pixels, you’re just fitting morepixels into each square inch. The same laws

apply with 3D textures. 4K is the maximumresolution Maya can bake maps (3ds Maxcan bake 8K maps—8,192 x 8,192).

When introducing the concept of 4K textures to video game developers, I got alot of cross-eyed looks. If you’re not using

compression you have to shrink these massive maps.I did a test one day with some skeptical developerswho commonly use 1K and 512k maps. I had a4K map on the right side of the screen and took adown-rezed 4K map and put it on the left. I asked the developers to guess what resolution the down-rezed map was. They all guessed 2K and whenI revealed they were looking at a 512 map, theirjaws dropped. Most game developers never

think above 2K and cer tainly don’t work at4K where you can properly manipulate pixelsand down-rez effectively.

One of the challenges I faced with the highvolume of asset orders in video gameproduction was the quality of textures.I was contracting out work to some of themasters like Chris Thunig (MPC London,Blizzard) and Paul Campion (the lead texture art ist for ‘Lord of the Rings’) andhad a stable of young kids fresh out of ar tschool. How was I to maintain quality?

The result was to create a massive texture

library that all artists would draw from.Working in conjunction with Peter Levius(3D.SK), we created a massive archiveof creature, skin, vehicle, and weaponsphotography. With hi-res photography,a young artist with proper art direction,can churn out face maps like the pros.

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PAUL

FEDOR



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68 ESSENCE The Face

PRE-HAIRCrEATING A BALDNESS MAP

Preparing for hair

A good texture artist should be able to pulla rabbit out of the hat. Old age, makeup, tissue damage, or a baldness map. Usual ly,in video game land I am using a hairbase. If a high-profile character comes up,I will have to generate a bald map.

Hair is a complicated beast in itself. It’sa much easier process to go ahead and

paint the hair in. This allows your hair artist to have a guide on hair lines. Once the hairartist sets the hairline, they can swap out the maps with the bald layer.

It’s a good idea to do hair and no hairoptions. You get into complicated issueswith the shadow of the hair falling on the

scalp, and a number of other issues. Sometimes thehair just doesn’t work, depending on what productionand what post house you are at. It’s a safe bet tohave the hair map standing by.

As you work with skin more and more, youbegin to apply medical procedures. Often,you start thinking like a plastic surgeon or a dermatologist. You think about how to stretch

skin and how to protect it from damage. You run into tricks on how to hide your scarsor seams. A baldness map is nothing more than skin graf ting.

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PAUL

FEDOR



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76 ESSENCE The Face

TIME FOR UPDATESREFINING THE DETAILS

Durable UVs

A scalable character is essential for anymass-production pipeline. With displacedsubdivision surfaces paving the futurefor games and movies, it’s the onlyway to work. Recyclable starter mapswith unchanging UVs play a key rolein the workflow.

Often, we will send off grey models for

approval to the client and start texturing.Without final client approval on modelrevisions, you are rolling the dice if you

start to texture. This is not a worry with standardizedUVs. Smart typology and well laid out unchangingUVs makes the texture maps as tough as metal.Often, the client comes back after a week andfinally realizes he wants a stupid change on abrow, or a forehead extended. My texture teamusually have the maps finished. Nine times out of ten you make a texture fix if the model changes. You have to fix the eyebrow or a corner of the

mouth, but that’s it. Standardized UVs cutback on texture fixes even with the mostdangerous clients.

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PAUL

FEDOR



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84 ESSENCE The Face

GETTING THE BUMPBUMP-MAPPING

I hate bump maps!

Have you ever seen what a bump map trulydoes? As an interesting experiment playaround with different settings. Basically,all a bump map does (at least in Maya)is cast an offset shadow on things likepores. If you ever played with the Embossfilter in Photoshop, it’s the same thing.It’s kind of nasty especially when you putit in lighting situations. In my opinion,

it’s one of the hardest things that lightershave to deal with.

Bumps are lame. Real photographic shadowsand detail come from displacement maps.I file normal maps in the same categoryas a bump on steroids. With displacedsubdivision surfaces, displacement mapswill give you the exciting detail wrinkles yousee on ZBrush Central.

Bumps are very tricky for tight skin.Many bumps that you see generated

on CGTalk are the repeating “orange peel skin”from a procedural texture. With the adventof ZBrush you dish off your model to the texture team and then back to mode ling. With ZBrush youcan extract all that wonderful photographic detail.Never use a procedural or hand-paint a bumpagain—it’s all in the photograph.

With the Inflate tool in ZBrush you can take

a wonderful 4K image map and “inflate” the sur face detail to create your high-frequency detail displacement. This not onlyworks for skin, but also ground planes forenvironment scenes. If you examine skinon a macro level, a ground plane (concreteor rocks) is just like the surface of skin. You can take a simple photo of rock from3D.SK, slap it on a simple plane, pull itinto ZBrush and boom! You can inflateall the detail in the photography into adisplacement for ground plains, build ings,or mountains.

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PAUL

FEDOR



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88 ESSENCE The Face

SHINY HAPPY PIXELSSPECULAR HIGHLIGHTS

Specularity maps

I have a slightly controversial way of doingspecularity maps. I actually paint with light that gives you highlights on every bump,ridge, and pore. In the end, whateverworks and looks good is the right way.This method was developed for a mass-production pipeline of 40-60 characterorders. Its key selling feature is a specularmap done in five minutes that any artist can

do. Traditionally, spec maps are a greyscaleversion of the color map. The artist wouldgo in and selectively lasso patches of skinand mark them for shininess with levelchanges. Anything white was greasy, andanything dark would be matte. Not easy invideo game land where half your crew arenot Paul Campion.

Specularity is misunderstood. The questionis: “how much do you see specularity inreal life?” When I came back to CG, I had the benef it of being: a trained illustrator; astudied photographer; and a music videodirector known for my cinematography.

On a shoot, I would pay the “Glam Squad”US$4,000 a day for rockstars (especiallyfemale artists), to make sure every timeI pulled the trigger there was NO shine onanyone’s face. Have you ever seen a makeupcommercial with the model looking greasy?

90% of everything you see on TV and movieshides the talent’s greasy/oily dark side.Most makeup artists come with a box of makeupgags to hide or bring out specularity. Most of the time they are hiding it . They have cream that givesa healthy sheen to skin. Some have shiny bitsof metal mixed into the cream to create a weirdmetallic specularity. The only time you seeserious gloss on a model, is usually in a cutting

edge fashion spread where they put “baby oil”on the model. Fashion photographers havecreated some of the most ingenious lightingschemes, crazy color corrects, and haveproduced some of the most exciting imagesin film in the last 15 years.

My advice to any young CG artist is before youmake digital images, you must understandhow they make analog images. If youwant to have serious discussions aboutspecularity, research top photographerslike Albert “Cyclops” Watson, PhillipdiCorcia, and Helmut Newton. Modernfashion photographers to catch are Nick

Knight, David La Chapelle, Sean Ellis,Andrea Giacobbi, and Zach Gold. Justbecause you work in CG doesn’t meanyou turn a blind eye what’s going onother fields. An artist’s purest functionis to perfect their power of observation.

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FEDOR



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92 ESSENCE The Face

EYE OF THE BEHOLDERSIMULATING THE HUMAN EYE

Eye on the prize

The eye is probably one of the hardest bodyparts to create. It’s hard even if you don’tgo for 100% realism—perhaps not themodeling so much as overall strategy, andshading. There’s translucency, refraction,reflection, caustics, and lots of details that have to fit together ver y exactly. Wealso use the eyes to communicate bodylanguage more than any other body part, so

everyone knows how it should look mostintimately. The easier part is modeling andshading the eyeball. I’ll show you how to do that firs t. The harder part is fitt ing the eyel ids to the eyeball and the lashes to the lids .

I’ll go through some common mistakes concerning the basic shape o f the lids at the end of this tuto rial.

Only a few years ago, the eyes used to bemuch harder to do. But, with HDRI, sub-surfacescattering, caustics, and much better referenceon the web they’re much less scary—almostfun. The modeling is easier if you approach itwith measurements and reference. The hardest

part is shading, and troubleshooting the testrenders. This comes with experience, so don’tget impatient and lose heart—once you’veperfected an eye you can use it as the basisfor almost any other character’s eyes.

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STEVEN

STAHLBERG



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100 ESSENCE The Face

A HEAD ABOVEPARAMETRIC HEAD CREATION

Making human heads

Everyone wants to build their own ultimatehead model—just once. Either you manage tobuild your ultimate head model, with perfect topology and UV mapping, or you don’t. Eitherway you probably never want to do it again!If you do succeed, then you want to reuse yourmodel again and again. You want to retargetit to any shape head you need. You want tobe able to lower and increase the resolution

as you want. You also want to keep all therigging and animation data you build up onone project and reuse it on every new project. You also hate the idea of using someone else’sparametric head. You hate the limitations that the software designer imposed. Worst still,you hate the aesthetic decisions some designermade when choosing the base head modelsand facial features. You’re right. I totally agree.

You should have the best, and it should be yourchoice. You should be able to reuse all youranimation. You should have complete controlover the topology, and you should be able toaccess the best of photo-fitting and hand-

modeling features. Fortunately, you can.

There is one mathematical approach toparametric head modeling that can do all of this and a lot more—principal componentanalysis. Let me explain: if you examinea big enough set of similar data then youcan do an analysis to see whether there aregroupings (principal components) of features that define the variations in the data. If youdo this for scanned head data—you takea large sample of full 3D scans (includingcolor data) of people’s heads—you comeup with about 140 principal components(parameters) that define a human head,

including skin and eye color maps. This is thebasis for one remarkable piece of software,FaceGen. This standalone application canencode and generate any human face.

It is based on a large set of full-color 3D scans ofpeople’s heads. It has no designer bias—it’s basedon real data. Because it’s parametric, you can: loadany topology head mesh you like, and everything stillworks; do automatic fits to photographs and generatefully parameterized heads ready to animate; blendface parameters or randomize them to generate setsof “relatives”; work with the most powerful andefficient manual modeling tools; and choose race,

sex, and age properties with ease because it’sbased on real population data.

I am belaboring the parametric point a bithere, but that’s because some things are justright—principal component approach to headanalysis and reconstruction is one example. Ifyou want a human head, this really is the bestway to go. As you will see, I have impor ted in the head and UV mapping we created earlierinto FaceGen, so I get all the benefits ofour own head model and mapping withoutlosing anything FaceGen offers.

I am using FaceGen as an example of the

best features you want from a parametrichead modeling system. Whether you willever use FaceGen or not, the point is thathuman heads share a lot of commonproperties and once you have a goodhead model, you want to reuse it asmuch as possible—if someone else hasdone the work for you, then use itand get on with the interesting aspectsof customizing, animating, and bringingyour character to life—it’s not cheating!

FaceGen is a standalone system thatoutputs models that you can bring intoany software, and it has a free demo

version. FaceGen also has a commercialSDK, so you can integrate its features intoyour own game like Bethesda Softworksdid with ‘The Elder Scrolls IV: Oblivion’.


mark

snoswell



101ESSENCE The Face




REAL SKINSUB-SURFACE SCATTERING

Rendering translucent skin

Better lighting is the main thing that hasimproved the quality of 3D renders in thepast decade. By that I don’t mean betterlighting design. I mean better simulation oflight behavior. With hindsight, there are fourareas of lighting simulation that turn out todeliver most of the jump in visual realism.In order of impact, these are: ambientocclusion; translucency; high-dynamic

range; and radiance. Here, we will focus on translucency. For our purposes, tr anslucentmaterials have a significant component of thei r look dominated by li ght that ente rs thematerial, is scattered and emerges backout again.

The current sub-surface scattering (SSS)methods stem from work Henrik WannJensen started in 1998. In a presentationat SIGGRAPH 2001, Jensen stunned thegraphics world with his elegant methodfor SSS. Just three years later, Jensenreceived an Academy Award for technicalachievement on SSS methods. Jensen’s

methods are a fast approximation to fullphoton-mapping and simulation that workvery well for most common translucentmaterials. Rarely has a new graphicsmethod leapt from academic to globalcommercial use so rapidly.

I had been working in the 3D fieldprofessionally for a long time before theadvent of SSS. I learnt all of the best techniques (and developed some of my own)

for faking a good look for skin—a look that faked someof the translucency properties of skin. Combine thesefakes with ambient occlusion and image-based HDRlighting models (we even wrote our own sphericalharmonic shaders), and you get pretty good skinrenders. I remember the excitement of Jensen’sBSSRDF presentation at SIGGRAPH 2001—but,I figured SSS would be slow and hard to usealthough it clearly did a better job for skin

than any fake ever cou ld. So, like manyothers I hung onto all my cheats and avoidedjumping to SSS until recently. Here is thelink to that seminal paper Jensen presentedat SIGGRAPH 2001: http://graphics.ucsd.edu/~henrik/papers/bssrdf/

Now SSS is widespread. All of the high-end 3D systems offer it. You can do greatSSS in real-time on most GPUs (GraphicsProcessing Units on graphics cards), soit’s starting to turn up in games. Havingupgraded to SSS shaders recently, I cansay that there is absolutely no reasonnot to use the SSS methods for skin—

well that’s unless you have a shot with the character lit only with blue light orvery low-level light like moonlight.

We are going to have a look at themental ray SSS Fast Skin shader asit’s available almost everywhere now.It turns out to be surprisingly fastand easy to use—and the resultsare a jump above anything you canever fake.


mark

snoswell



109ESSENCE The Face




UNDER THE SKINPOOR MAN’s SSS

Sub-surface scattering

Sub-surface scattering shaders (SSS) havebeen one of the most complicated andmisunderstood subjects in CG. Video gamesusually don’t have the time and money to pay heavy-duty shader writers. Often, there is not enough time for complicatedsub-surface settings to be tweaked. Enter‘The Poor Man’s SSS’. I decided to beginresearch on a map-driven SSS shader.

All you had to do was to plug in the maps,and it would work in the default settings.

On every team, there will be a range of talent. I had to come up with a system thatwas usable on a mass-production scale,yet easy enough for kids coming out ofart school to understand. In the end,shaders and textures depend on a lotof things, and this approach is just one

of them. It has been proven on several productionson more than 80 characters. It works with all typesof skin including old, African American, Asian,Caucasian, and tissue damage. All this generatedfrom one map, with 100% registration, down toa pore level.

There is much hullabaloo over skin,which is less than a millimeter thick.

If you study Rembrandt’s paintings he reallyonly used about five glazes on his faces.If Rembrandt can do photo-real skin in fivelayers, why can’t CG? The SSS shaderis nothing more than a layered shader.Human skin is really not that complicated.Deep tissue, bone, and muscle are partof backface scattering, but that is not par tof the skin. It’s actually only two parts: the epidermis and the subdermis.


PAUL

FEDOR



117ESSENCE The Face




lights, camera, renderlighting and rendering monika

Lighting fit for a super model

The lighting direction for this project waspretty straightforward. Basically, we arecreating a super model type of image, whichmeans make her look hot! The best way to tackle any lighting project is to translate the stage direction, like “make her looklike a super model” into something useful to you as a lighter. What makes a womanbeautiful? Deep, liquid eyes, full lips, smooth

clean skin, and a good form on the face.Luckily, the textures and model on thisparticular project are top notch, so the formand smooth skin are pretty much in place.Also, you need to understand the oppositeof your objective. Male models are all aboutstructure. Lighting should emphasize highcheekbones, strong jaw line, strong eyes,etc. So those are things we probably want toavoid with this lighting set-up.

To get underway, I first took a look at themodel to see if there was anything weneeded to be careful about when lighting andrendering. At this point, you need to make

sure the geometry is in good shape and theUVs make sense. If you are planing to usesomething like displacement, it is paramount that the surface and UVs are super clean, oryou are in for a lot of fix-it headaches. LikeI said, the model is of very high quality, sowe are covered there. The next thing is tolook at the textures. These are also supernice. However, all the textures were providedat 4K. Excellent for image quality—possibleheadache in the pipeline. The demands forrealism and image fidelity are always on the rise, so you have to find an economicalway of dealing with the large file sizes.

This is where map textures with mental ray come in. Theywill save you—end of story. I have had multi-gigabyte textures burning over a hundred processor render farmwith absolutely no problem or network bottle-neckingdue to MAP. They are magic, use them!

So now I am ready to start rendering. I came into this project late, and the timeline was crunched,so speed was a critical concern. I needed to

get a photographic render, and couldn’t afford to spend hours setting up lights. I neededa shortcut. Enter Image Based Lighting (IBL).IBL might be the greatest thing to ever happen to CG lighting! It doesn’t do color bleed,or photon mapping. It does do amazingdiffuse lighting and soft shadows. In short,it will get you to real faster than any othermethod. The downside: if you don’t knowwhat you’re doing, it can be prohibitivelyexpensive to render. As the name implies,IBL is all about the image you use, so youmust choose wisely, selecting one thatrepresents the illumination setup you arelooking for. There’s no better image type

for IBL than HDRI. Now that we have ourillumination model, it’s time to look at the eyes. Eye’s are about three things:reflection; refraction; and specularhighlights. Reflection is obvious—youneed the eyes to look shiny and brightagainst the soft skin of the face. Theyneed to look liquid, which has a lot todo with using the cornea to refract theiris and attenuate the light traveling through it. Finally, you need a “figure”light to pop a hot spot in the eye.I used an area light that was just linked to the cornea geometry to achieve this.


matt

hartle



125ESSENCE The Face




COSMETICS IN PIXELSSIMULATING Makeup

Makeup isn’t just for girls

If you want photo-real use a photograph. You can have your bes t illust rator sweatover painting makeup, but for time, money,and quality, please use photographs.

With a high-resolution photographicpipeline, you can settle the argument onmakeup. You can’t compare a 16-megapixelphoto, taken by a decent photographer,

with professional stylist to hand-painting. Makeup isn’t just for the girls.

Often with video games we get a large quantityof soldiers with camouflage face paint. We go outand get real army surplus military-grade facepaint and shoot it. You can try lame colorcorrections or various airbrush tricks, butnothing beats a great photograph. It’s standardprotocol to shoot with and without makeup.Whether it’s lipstick red or ‘ApocalypseNow’ green, if you want photo-real use

a photograph. You might even get L’Oréalas a client too.


PAUL

FEDOR



133ESSENCE The Face




BrUISING & SCARRINGSIMULATING TISSUE DAMAGE

The dark side

Mughahhahaha! Welcome to my darkside. If you want to do creature textures,you might want to pay attention to this now.

Protecting photographs is nice, but whena scar job comes along, it’s a chance toprove your chops as a texture artist. With aphotographic pipeline, it’s not a question ofa scar, but what kind of scar? Do you want

an acid scar, burn scar, battle scar, bruise,cut, laceration, or just a plain birth defect. One of the most important and valuable things I did for Sony was to create amassive hi-resolution texture library. Weshot planes, tanks, weapons, half-tracks,and missiles. Any type of metal for a vehicle

or ship that a texture artist could ever want, we havearchived. We shot rare lizards and bats from ‘TheMuseum of Natural History’ for all types of creatures,bats, dragons, or monsters. We shot the armorcollection at ‘Metropolitan Museum of Art’ for every type of armor you could want. Just when I thoughtI had one of the craziest collections of hi-resphotography, I came across 3D.SK’s collectionof dead cow pictures.

Part of the texture or matte painter’s job is to have a crazy archive of photos. WhenI saw Peter’s collection of photos from theslaughter house, I knew all my needs forscar photography were satisfied. If you don’thave a weak stomach, then this tutorial isfor you.


PAUL

FEDOR



143ESSENCE The Face




AGING MONIKA PAINTING IN THE YEARS

Skin-deep beauty

Aging is one of the fun tasks of a textureartist. The true power of beauty is in the texture ar tist’ s hands. With a hi-resphotography pipeline aging becomes veryspecific. A vague question like “how old isold?” becomes “do you want Monika age50? or age 75? or Monika the mummy?”

In fact, it is very hard to create a young

beautiful face from a CG point of view. Young people have rea lly tight pores,which make for really weak bump maps onsmooth skin. Villains and older people havereally large pores which really make forgreat specular and bump maps. So olderis often easier.

Strange things happen to the skin whenit ages. Skin actually gets thinner with time, so whatever is in the subdermallayer really starts to peak through. IfI skinned Monika alive, her epidermiswould have virtually no color in it.

The seven layers of epidermis (commonly thought ofas your skin) are a semi-translucent layer kind of likea latex glove. This layer has no blood in it.In essence, the human body is a bag of water,bones and blood. The subdermis is where all theaction is, with fat, blood, bruises, pigmentation,nerves, red, blue, and yellow veins.

As the body gets older, anomalies happen in

the skin—especially in the subdermis. Skinsags and wrinkles. Blood circulation slowsdown, because your heart is weakening. Thismeans less oxygen in the blood and blueishskin. A lot more blue veins occur. Weird fattydeposits pop up leaving blemishes. Dirt,crap, melanoma, and the tough road of lifeitself get embedded in your skin as youage. Your pores get bigger, and dirt getsin them. Zits become blackheads. Stressand income all play into the aging of yourskin. It’s a very interesting concept toargue that it’s age, beauty and life thatmakes the skin.


PAUL

FEDOR

essence theface modeling and texturing

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