jungle shot from “madagascar” cnm 190, pt...

CNM 190, pt 2CNM 190, pt 2Advanced Digital AnimationAdvanced Digital Animation

Lec Lec 03 : Art Direction on Madagascar / Effects 103 : Art Direction on Madagascar / Effects 1Shannon Jeffries, Shannon Jeffries, PDI/Dreamworks PDI/Dreamworks ((Art Director, MadagascarArt Director, Madagascar))

Marilyn Friedman, Marilyn Friedman, PDI/DreamworksPDI/Dreamworks (Outreach)(Outreach)Dan Garcia, EECS (co-instructor)Dan Garcia, EECS (co-instructor)

Brian Brian BarskyBarsky, EECS (co-instructor), EECS (co-instructor)Greg Niemeyer, Art (co-instructor)Greg Niemeyer, Art (co-instructor)

Jeremy HuddlestonJeremy Huddleston,, EECS (TA) EECS (TA)Ashley EdenAshley Eden,, EECS (TA) EECS (TA)

Jungle shot from Jungle shot from ““MadagascarMadagascar””

2/13Madagascar Art + Effects 1http://inst.eecs.berkeley.edu/~selfpace/CNM190, pt 2

OverviewOverview

ShannonShannon Art directingArt directing

MadagascarMadagascar Critiquing ourCritiquing our

artistic look forartistic look forour two piecesour two pieces

DanDan Special EffectsSpecial Effects

HistoryHistory MechanicalMechanical OpticalOptical

Pure CG film FXPure CG film FX FluidsFluids ParticlesParticles

MarilynMarilyn OpportunitiesOpportunities

@ PDI for you!@ PDI for you!


Special Effects (SFX) HistorySpecial Effects (SFX) History

The first special effect was done in 1895 who used aThe first special effect was done in 1895 who used adummy to simulate the beheading of Mary Q of Scots!dummy to simulate the beheading of Mary Q of Scots! ““Stop tricksStop tricks”” like this are still used on like this are still used on YouTube YouTube today!today!

Used Used ““when scenes canwhen scenes can’’t be realized by normal meanst be realized by normal means”” In CG animations, very similar case!In CG animations, very similar case! WhatWhat’’s s ““normalnormal””??

en.wikipedia.org/wiki/Special_effectswww.filmsite.org/visualeffects1.html

CGI special effects used in Star Wars Episode IIICGI special effects used in Star Wars Episode III1895: The first SFX!1895: The first SFX!


Mechanical EffectsMechanical Effects

Aka Aka ““practicalpractical”” or or““physicalphysical”” effects effects Used during live shotsUsed during live shots

These includeThese include Mechanized propsMechanized props SceneryScenery Bullet hitsBullet hits PyrotechnicsPyrotechnics Wind, rain, snow, etcWind, rain, snow, etc

Outside the scope ofOutside the scope ofthis classthis class –– Mech Mech E?E?

en.wikipedia.org/wiki/Special_effects

R2D2 is a mechanical special effectR2D2 is a mechanical special effect


Optical EffectsOptical Effects

Aka Aka ““visualvisual”” (CGI) or (CGI) orphotographicphotographic””(optical printer) effects(optical printer) effects Manipulations of theManipulations of the

photographed imagesphotographed images

These includeThese include Stop tricks, miniatures,Stop tricks, miniatures,

mattes, dolly zoom,mattes, dolly zoom,bluescreenbluescreen, wire, wireremoval, morphing,removal, morphing,match moving,match moving, andandcomputer-generatedcomputer-generatedimageryimagery (CGI)(CGI)

en.wikipedia.org/wiki/{Special_effects, Optical_printer}

An optical printer used for optical effectsAn optical printer used for optical effects

Apple Shake, for compositing CGI SFXApple Shake, for compositing CGI SFX


In purely CG films, what are SFX?In purely CG films, what are SFX?

Typically things thatTypically things thatrequire specific technicalrequire specific technicalattentionattention

Natural phenomenaNatural phenomena Smoke,Smoke, fire, fog, snowfire, fog, snow Fluids (water, rain, etc)Fluids (water, rain, etc)

Character-related SFXCharacter-related SFX Cloth simulations, hair, furCloth simulations, hair, fur Footsteps in sandFootsteps in sand Crowds & mobsCrowds & mobs

Often, a problem starts asOften, a problem starts asSFX and evolves into a toolSFX and evolves into a toolthat animators simply usethat animators simply usein the pipeline!in the pipeline!

CG Smoke by Ron CG Smoke by Ron FedkiwFedkiw(with Andrew (with Andrew Selle Selle and Nick Rasmussen)and Nick Rasmussen)


FluidFluid SimulationSimulation

When to use fluids?When to use fluids? Ocean simulation? No!Ocean simulation? No!

ThatThat’’s easy enough withs easy enough withPerlin Perlin noise and waves ofnoise and waves ofdifferent frequenciesdifferent frequencies((called 2D height fieldcalled 2D height fieldsimulations)simulations)

Typically with mediumsTypically with mediums(fire, smoke, bodies of(fire, smoke, bodies ofwater with water with splashinesssplashiness,,fog, snow driftsfog, snow drifts

Fluids interacting withFluids interacting withother other sims sims (cloth, other(cloth, otherfluids, melting) is hard!fluids, melting) is hard!

graphics.stanford.edu/~fedkiw/www.cs.berkeley.edu/b-cam/

Multiple Interacting Liquids by Ron Multiple Interacting Liquids by Ron FedkiwFedkiw((w/Frank Losassow/Frank Losasso, Tamar , Tamar Shinar Shinar & Andrew & Andrew SelleSelle))

Fedkiw, O’Brien fluid sims


FluidFluid Simulation BasicsSimulation Basics

Navier-Stokes Navier-Stokes equationsequations These describe the motion ofThese describe the motion of

fluids (liquids & gases)fluids (liquids & gases) Derived from conservation ofDerived from conservation of

mass, energy,mass, energy, angularangularmomentummomentum & momentum& momentum

Momentum equationMomentum equation Really just F=ma, in that itReally just F=ma, in that it

tells you how fluidtells you how fluidaccelerates due to forcesaccelerates due to forcesacting on itacting on it

Incompressibilty condIncompressibilty cond.. Fluid volume in = outFluid volume in = out

AdvectionAdvection is the flow of is the flow ofparticles through field particles through field uu

www.cs.ubc.ca/~rbridson/fluidsimulation/en.wikipedia.org/wiki/Navier_Stokes

IncompressibilityIncompressibility conditioncondition

Momentum equationMomentum equation

uu is velocity is velocity ρρ is density is density

(water = 1000kg/m(water = 1000kg/m33)) pp is pressure is pressure gg is gravity, or is gravity, or ““animatoranimator”” νν is is kinematic kinematic viscosityviscosity

How viscous is fluidHow viscous is fluid ∇∇ pp is pressure gradient is pressure gradient ∇∇ · ·uu is divergence is divergence of velocityof velocity


FluidFluid Simulation MeshesSimulation Meshes

Lagrangian Lagrangian viewpointviewpoint Moving meshMoving mesh World is a particle systemWorld is a particle system Track where particles goTrack where particles go ““Floating Floating w/wind w/wind in balloonin balloon””

FeaturesFeatures Good for solidsGood for solids Bad for fluidsBad for fluids

Significant deformation andSignificant deformation andtopology changetopology change

www.cs.ubc.ca/~rbridson/fluidsimulation/en.wikipedia.org/wiki/Navier_Stokes

Eulerian Eulerian viewpointviewpoint Static meshStatic mesh Point in space fixedPoint in space fixed Measure as things go byMeasure as things go by ““On ground, wind blowsOn ground, wind blows””

FeaturesFeatures Good for fluidsGood for fluids Bad for solidsBad for solids

Harder to track movingHarder to track movingmaterial quantitiesmaterial quantities


Particles : cheap & useful!Particles : cheap & useful!

Particle parametersParticle parameters Spawning rate, angleSpawning rate, angle Initial velocityInitial velocity vectorvector Particle lifeParticle life Color and variationsColor and variations Should have noise here!Should have noise here!

SimulationSimulation Update,Update, Render, repeatRender, repeat Friction, objects, gravity,Friction, objects, gravity,

flows (e.g., vector fields)flows (e.g., vector fields)modify location + velocitymodify location + velocity

Particle-particle collisionsParticle-particle collisionsusually not checkedusually not checked

Particle death (fadeParticle death (fade α→α→0)0)

en.wikipedia.org/wiki/Particle_systems

accad.osu.edu/~mpalazzi/AC753W05/Computer%20Graphics%20World%20-%20ANTZ-PIRATION.pdf


Particles : Particles : ……and ubiquitousand ubiquitous Particles used forParticles used for

Spray, drips, rainSpray, drips, rain surging & pouring watersurging & pouring water DripsDrips ExplosionsExplosions

Particles allow binding!Particles allow binding! One can bind anything to aOne can bind anything to a

particle, very usefulparticle, very useful Particles affect theParticles affect the

surroundings sometimessurroundings sometimes In the shot at the right, waterIn the shot at the right, water

carries objectscarries objects in the hallin the hall RenderingRendering

Metaballs Metaballs commoncommon

www.nextlimit.com/realflow/cs_poseidon.htm

Final composite for Poseidon Final composite for Poseidon ““BroadwayBroadway”” shot shot

CIS Hollywood (small effects house) withCIS Hollywood (small effects house) withearlyearly RealFlow RealFlow rigid body dynamics testrigid body dynamics test


FluidFluid Simulation SoftwareSimulation Software

MayaMaya (only in(only in Autodesk Autodesk MayaMaya

Unlimited)Unlimited) 2D Solver (height field)2D Solver (height field) 3D Fluid Solver3D Fluid Solver

Realflow Realflow (RF4)(RF4) Python scripting at heartPython scripting at heart Used in many big filmsUsed in many big films Fluids, surfaces, particlesFluids, surfaces, particles

HoudiniHoudini Particle motionParticle motion Fire, white water, insects,Fire, white water, insects,

crowd crowd simssims

www.autodesk.com/mayawww.nextlimit.com/realflow/

www.sidefx.com

Water simulation in Houdini MasterWater simulation in Houdini Master

Software Demos

RF4RF4


ConclusionConclusion

Particles and Fluids and a world of effectsParticles and Fluids and a world of effects Fluid techniques now readily available in todayFluid techniques now readily available in today’’s SWs SW 2D height fields used for simple ponds, oceans2D height fields used for simple ponds, oceans If solving fluid problem, Euler solution on fixed gridIf solving fluid problem, Euler solution on fixed grid

This is still a very active area of research. ItThis is still a very active area of research. It’’s not solved!s not solved!

Shot from Madagascar with ocean water effects in the background

jungle shot from “madagascar” cnm 190, pt...

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