the road to victory: procedural modeling for ea sports’ nascar thunder wesley grandmont iii...

The Road to Victory:The Road to Victory:Procedural Modeling for Procedural Modeling for

EA Sports’ EA Sports’ NASCAR NASCAR ThunderThunder

Wesley Grandmont IIIWesley Grandmont IIITechnical Art DirectorTechnical Art DirectorElectronic Arts-TiburonElectronic Arts-Tiburon

March 2005March 2005

Introduction

Intro VideoIntro Video

The Road To Victory: Procedural Modeling for EA Sports’ The Road To Victory: Procedural Modeling for EA Sports’ NASCAR NASCAR ThunderThunder

presented by Wes Grandmont III, Technical Art Director, Electronic Artspresented by Wes Grandmont III, Technical Art Director, Electronic Arts

Introduction

• About the presenterAbout the presenter– Background in Games/Illustration/BroadcastBackground in Games/Illustration/Broadcast– 7+ years in the gaming industry7+ years in the gaming industry– 4 years in field of technical art4 years in field of technical art

• Created art pipelines and tools for Nascar Thunder, Created art pipelines and tools for Nascar Thunder, NFL Street, Madden NFL & NCAA FootballNFL Street, Madden NFL & NCAA Football

– Created 30+ scripts, plug-ins and character Created 30+ scripts, plug-ins and character rigs currently in use by 4 AAA game rigs currently in use by 4 AAA game franchises.franchises.



Introduction

• Technical Art at EA-TiburonTechnical Art at EA-Tiburon– The team The team – Role on projectsRole on projects– ResponsibilitiesResponsibilities– Pre-requisitesPre-requisites



Art Dev

TechArt

Production

• A Brief History of A Brief History of NASCAR NASCAR ThunderThunder

• Procedural Modeling ConceptsProcedural Modeling Concepts• TrackbuilderTrackbuilder: A Case Study: A Case Study• Maya/MEL Design Tips & TricksMaya/MEL Design Tips & Tricks• Q & AQ & A

Overview



• NASCAR 2001 Legacy IssuesNASCAR 2001 Legacy Issues– Inherited Code & Art Assets from `01Inherited Code & Art Assets from `01

• visual/technical inaccuraciesvisual/technical inaccuracies• non-Maya resourcesnon-Maya resources

• Many challengesMany challenges– Reduce creation timesReduce creation times– Increase QualityIncrease Quality– First racing game for TiburonFirst racing game for Tiburon

The Backstory



• Pro·ce·dur·alPro·ce·dur·al– adjective: relating to or comprising memory or knowledge concerned with how to manipulate symbols, concepts, and rules to accomplish a task or solve a problem.

Source:Merriam-Webster Medical Dictionary, ©2002 Merriam-Webster,Inc.

Concepts



• Procedural ModelingProcedural Modeling– Wes’ definition: Wes’ definition: Rule-based modeling, Rule-based modeling, involving an algorithmically involving an algorithmically configurable representation of the configurable representation of the model data.model data.

Concepts



• Procedural ResearchProcedural Research– NoiseNoise

• K.Perlin. K.Perlin. Improving Noise, Computer Graphics; Vol. 35 No. 3

– City BuildingCity Building• Y. Parish & P. Müller. Procedural Modeling of Cities. SIGGRAPH `01

– Plant Generation (L-systems)Plant Generation (L-systems)• Prusinkiewicz, P. and Lindenmayer, A. The Algorithmic Beauty of Plants.

New York: Springer-Verlag, 1990.

– Fractal LandscapesFractal Landscapes• F.K.Musgrave. F.K.Musgrave. Fractal Landscapes in Their Natural Context, SIGGRAPH

`04Course Notes from The Elements of Nature: Interactive and Realistic Techniques

Concepts



• Why model procedurally?Why model procedurally?– Fast content generationFast content generation– Quick iterationsQuick iterations– Consistent quality/accuracyConsistent quality/accuracy– Allow more time for detailsAllow more time for details– Reduces development costsReduces development costs

Concepts



• Why not model procedurally?Why not model procedurally?– Model is unique or a one-offModel is unique or a one-off

• e.g. “The Thinker”, sports trophy, main e.g. “The Thinker”, sports trophy, main character character

– cost to model by hand < cost to cost to model by hand < cost to implement procedurallyimplement procedurally

Concepts



• 5 steps to procedural modeling5 steps to procedural modeling– 1. Classify the models1. Classify the models– 2. Abstract the classes2. Abstract the classes

• defining attributes?defining attributes?

– 3. Identify special cases3. Identify special cases – 4. Test/Refine/Re-test the abstraction4. Test/Refine/Re-test the abstraction

• Can I make all my variations?Can I make all my variations?

– 5. Implement final abstraction5. Implement final abstraction• Know the limitations of the abstractionKnow the limitations of the abstraction• Allow room for improvementsAllow room for improvements

Concepts



• Hidden AdvantagesHidden Advantages – Know everything about your world!Know everything about your world!– ““Smart models” Smart models” – Framework for future tool developmentFramework for future tool development

Concepts



• When to cut the procedural When to cut the procedural cord?cord? – If you need to make modifications that If you need to make modifications that

the abstraction cannot support.the abstraction cannot support.– And -And -

– The game code does not require that the The game code does not require that the abstraction be maintained in-game.abstraction be maintained in-game.

Concepts



• Quick TangentQuick Tangent – Libraries & World Building ToolsLibraries & World Building Tools– Close cousins of procedural modelingClose cousins of procedural modeling

Concepts



• Nascar Thunder 2002 Nascar Thunder 2002 ChallengesChallenges– Create 26 tracks in 6 monthsCreate 26 tracks in 6 months– Length accuracy criticalLength accuracy critical– Accurate track measurementsAccurate track measurements– Visually accurate Visually accurate – Plan for gameplay tuning changesPlan for gameplay tuning changes

Trackbuilder: A Case Study



• Laying the foundationLaying the foundation– Hired contractor to travel to all tracksHired contractor to travel to all tracks

• Gather reference photos and mesurementsGather reference photos and mesurements

– Get top down layouts of all tracksGet top down layouts of all tracks• Visual guide, defining the shape of each trackVisual guide, defining the shape of each track




• Step 1: Classify the modelsStep 1: Classify the models– Closed loop tracksClosed loop tracks– Press boxesPress boxes– CrowdsCrowds– Track interior/exteriorTrack interior/exterior– Pit roadPit road– Interior wallsInterior walls– PropsProps




• Step 2: Abstract the classesStep 2: Abstract the classes– Class: Closed loop TrackClass: Closed loop Track

• Track (length, width, banking,etc.)Track (length, width, banking,etc.)• Right and Left Sides Right and Left Sides

– Aprons (width, banking)Aprons (width, banking)– Walls (height, width, depth, tilt, end caps)Walls (height, width, depth, tilt, end caps)– Fences (height, angle, top length, top angle)Fences (height, angle, top length, top angle)

• Post-processing attributesPost-processing attributes– Edge alignmentEdge alignment– Measuring locationMeasuring location




• Step 3: Step 3: Identify any special Identify any special casescases – Pit roadPit road

• Need system for dealing with pit road Need system for dealing with pit road geometrygeometry

– Road CoursesRoad Courses• e.g. Watkins Glene.g. Watkins Glen• Elevation changesElevation changes




• Step 4: Step 4: Test/Refine/Re-test Test/Refine/Re-test – TestTest

• Do any tracks have attributes that aren’t part Do any tracks have attributes that aren’t part of the abstraction?of the abstraction?

– RefineRefine• Back and forth to settle on final set of track Back and forth to settle on final set of track

attributesattributes

– Storage of track attributes on Maya nodeStorage of track attributes on Maya node– ““version” attribute critical! version” attribute critical!




• The Trackbuilder workflowThe Trackbuilder workflow – ““Model railroad” paradigmModel railroad” paradigm– Layout a NURB curve shape Layout a NURB curve shape – Build track from procedural NURB Build track from procedural NURB

“sections”“sections”– Post-process sectionsPost-process sections– Auto-generate polygonal LOD’s with Auto-generate polygonal LOD’s with

proper UV mapping & default materialsproper UV mapping & default materials




• Step 5: Implement Final Step 5: Implement Final AbstractionAbstraction– TrackbuilderTrackbuilder

• 12 “modules” 12 “modules” • ~20,000 lines of total MEL code~20,000 lines of total MEL code• Modules implement distinct procedure setsModules implement distinct procedure sets• ““TB_” prefixTB_” prefix







TB_trackBuilderUI

TB_trackLength

TB_shaderMgrTB_sectionNav

TB_sectionChop

TB_sectionBuild

TB_progressWin

TB_makeLODSource TB_makeLODPoly

TB_dataManager

TB_autoWrapDeform

TB_addLODPart

NU

RB

MO

DU

LES

PO

LY M

OD

ULE

S

DemoDemo




• Trackbuilder statsTrackbuilder stats– Took ~5 months to develop Took ~5 months to develop

• re-factored 3x (new features, optimizations)re-factored 3x (new features, optimizations)

– Used on Nascar Thunder franchise for 4 years:Used on Nascar Thunder franchise for 4 years:• 2002,2003,2004,20052002,2003,2004,2005

– Saved ~10,400 man hours over 4 yearsSaved ~10,400 man hours over 4 years



Trackbuilder: Lessons Learned

• In hindsight...In hindsight...– Allow adequate time for the test/refine/re-test Allow adequate time for the test/refine/re-test

step.step.– Use plug-ins for Maya component operationsUse plug-ins for Maya component operations– TrackbuilderTrackbuilder “section” could have been custom “section” could have been custom

Maya node.Maya node.



Trackbuilder: Lessons Learned

• Trackbuilder OffspringTrackbuilder Offspring– PhysicsTrackPhysicsTrack

• Auto-tesselation for physicsAuto-tesselation for physics– Critical for gameplay tuningCritical for gameplay tuning

• Auto-creation of simplified geometryAuto-creation of simplified geometry– Control memory foot print for physics Control memory foot print for physics




• Trackbuilder OffspringTrackbuilder Offspring– Pole PlanterPole Planter

• Auto-placement of instanced 3D fence-Auto-placement of instanced 3D fence-postsposts

• Assumptions made about Assumptions made about TrackbuilderTrackbuilder generated catch-fences and wallsgenerated catch-fences and walls




• Trackbuilder OffspringTrackbuilder Offspring– bakeFenceShadowbakeFenceShadow

• Auto-generation of cast shadow Auto-generation of cast shadow geometrygeometry

• Use simplified physics track as input Use simplified physics track as input




• Tips for large MEL scriptsTips for large MEL scripts– Separate UI from main scriptSeparate UI from main script– Only one global proc (with switch Only one global proc (with switch

statement)statement)– ModulesModules– ProceduresProcedures– Arrays Arrays – Manage memory when possibleManage memory when possible– String packing & data structuresString packing & data structures



Maya Tips & Tricks

• Dynamic Curve Sampling: an Dynamic Curve Sampling: an interactive trick interactive trick – Technique developed for Technique developed for TrackbuilderTrackbuilder tool tool

• Great for procedural modelingGreat for procedural modeling

– AnimCurve nodes for interactive AnimCurve nodes for interactive deformation!deformation!

– Allows real-time tweaking of curves and live-Allows real-time tweaking of curves and live-update in Maya.update in Maya.

– Use to drive any scalar valueUse to drive any scalar value• e.g. transform values, blendshape valuese.g. transform values, blendshape values



Maya Tips & Tricks

• Dynamic Curve Sampling: explained Dynamic Curve Sampling: explained



Maya Tips & Tricks

//1. Create node with two attributes

createNode transform -name myControl;

//2. Add dynamic attributes and set driven keyaddAttr -ln dist -h true -at "float" myControl;addAttr -ln height -h true -at "float" myControl;

setAttr myControl.dist 0;setAttr myControl.height 0;setDrivenKeyframe -cd myControl.dist myControl.height;

setAttr myControl.dist 1;setAttr myControl.height 20;setDrivenKeyframe -cd myControl.dist myControl.height;

• Dynamic Curve Sampling: explainedDynamic Curve Sampling: explained



Maya Tips & Tricks

//3. Make some objects and create the curve sampling expressionsstring $expr,$sphere[];int $i,$transX = 0;for ($i=0; $i<10; $i++) {$sphere = `polySphere`;setAttr ($sphere[0] + ".tx") $transX;$transX += 2;$expr = "ty = myControl.height;"; $expr += "float $temp[] = ";$expr += "(`keyframe -ev -f "+((float)$i/9)+” -q myControl.height`);";$expr += "ty = $temp[0];";expression -ae 0 -o $sphere[0] -s $expr;clear $sphere;}

• Dynamic Curve Sampling: explainedDynamic Curve Sampling: explained– Looping expression creationLooping expression creation

• Setup control for multiple objects/attributesSetup control for multiple objects/attributes

– Multiple objects can then be “sculpted”Multiple objects can then be “sculpted”– Use Graph Editor to tweak “height” curve on Use Graph Editor to tweak “height” curve on myControlmyControl node node

• -or- make a custom GUI-or- make a custom GUI



Maya Tips & Tricks

Dynamic Curve Dynamic Curve Sampling DemoSampling Demo



Maya Tips & Tricks

NOTE: Copy MEL from previous slides into Maya Script Editor window and hit “Enter” on the number pad to execute.

For their dedication, feedback and understanding!For their dedication, feedback and understanding!Nascar Thunder 2002 & 2003 track team members:Nascar Thunder 2002 & 2003 track team members:• Dante Duphorne, Mark Flewelling, Ron Amador, Ymir Dante Duphorne, Mark Flewelling, Ron Amador, Ymir

Jonnson, Dave KeimachJonnson, Dave Keimach

For the opportunity to present this lecture:For the opportunity to present this lecture:• Steve Chiang, Rob Moore, Dave Swanson, Joe Stallings, Steve Chiang, Rob Moore, Dave Swanson, Joe Stallings,

Electronic ArtsElectronic Arts

Thank You



Thanks for coming!Thanks for coming!

Questions?Questions?

Q&A



Contact Info: [email protected] Info: [email protected] include “GDC05_Lecture” in the subject line Please include “GDC05_Lecture” in the subject line

www.www.grandmontstudiograndmontstudio.com.com

http://www.grandmontstudio.com/



the road to victory: procedural modeling for ea sports’ nascar thunder wesley grandmont iii...

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procedural modeling

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wes grandmont

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