Computers in Film Making
Snow White (1937)
Computers in Film Making Slide 1
Snow White - Disney’s Folly
Original Budget $250,000Production Cost $1,488,422Frames 127,000Production time 3.5 years
but
Gross revenue $184,925,486
Moral:
• Animated films are high risk, but very profitable
• Creation of these films required enormous human input
Computers:
• Could automate some of the human tasks
Computers in Film Making Slide 2
212D Graphics - Tweening
By the 1970s computers were sufficiently powerful tohelp with drawing cartoons, and assembling “cell based”animation.
Some work was done to support “tweening” - drawing theframes that go between two keyframes - but this provedhard to automate.
Computers in Film Making Slide 3
3D Animation - Polygon rendering
Military simulator circa 1990
Early computer animationsystems (flight/militarysimulators) used planarpolygons to create 3Dworlds.
Costs were high and thequality was too low forfilm.
Computers in Film Making Slide 4
The Graphics Pipeline: 1980
Computers in Film Making Slide 5
Silicon Graphics Reality Engine (1992)
Nowadays you can buy afar more powerful Graph-ics Processing Unit to pluginto your PC.
Special purpose hardwarefor interactive graphics
OpenGL: General purposedesign language
Computers in Film Making Slide 6
Polygon Rendering in films
Toy Story (1995)
Computers in Film Making Slide 7
Ray Tracing (1980)
Each pixel of the image is computed independently
Reflections and refractions can be created.
Computers in Film Making Slide 8
Ray Tracing Examples
morphine molecule (1983)
Computers in Film Making Slide 9
Ray Tracing Examples
Street Scene (2011)
Computers in Film Making Slide 10
Ray Tracing Examples
Titanic (1997)
Computers in Film Making Slide 11
Gorilla Filmstars - are they Computer Generated?
Computers in Film Making Slide 12
Gorilla Filmstars - are they Computer Generated?
King Kong 1976 King Kong 2005 Real Gorilla
Real Gorilla King Kong 1933 Trading Places 1989
Computers in Film Making Slide 13
Motion Capture
One approach to createrealistic movement is to usemotion capture - for exampleGollum in the Lord of theRings films.
The actor’s movements arefilmed and turned into 3Dmovements, then mapped tothe avatar.
The Fellowship of the Rings 2001
Computers in Film Making Slide 14
Complexities of Motion
Natural motions arecomplex, as shown byEadweard Muybridge’shorse photographs of(1878).
Both the geometric mo-tion and the dynamics(velocity and accelera-tion) are difficult to de-scribe.
Computers in Film Making Slide 15
Skeleton based Animation
The skeleton geometry is well defined and constrains themotion.
However there are many different types of joints.
Computers in Film Making Slide 16
Inverse Kinematics
One approach to moving a skeleton is to specify how theextema (hands feet) move, and calculate the positions ofthe other joints. Each link is specified in the coordinatesystem of its predecessor
However there is no unique solution, so there is an openresearch question - How do we constrain the solution toachieve natural movement?
Computers in Film Making Slide 17
Amorphous Objects
A major challenge for the com-puter scientist was (and stillis) creating amorphous movingobjects such as fire, smokeclouds and water.
The problem has two aspects:
• modelling• rendering
Computers in Film Making Slide 18
Particle Systems
One modelling method is to ap-proximate amorphous objectsby a discrete set of small par-ticles. Particles can have:
• Mass• Position• Velocity• Temperature• Shape• Lifetime
Particle Fountain
Computers in Film Making Slide 19
Particle Fires - The Wrath of Khan (1983)
Particle systems were first usedin film to create fire in the film“The Wrath of Khan”.
The Genesis Bomb:
• A special bomb is droppedon a baren planet
• The bomb and fire createlife on the planet
(Doesn’t sound very likely to me)
Computers in Film Making Slide 20
Rendering Particle Fires
The Wrath of Khan renderedeach particle by drawing a lineshowing its path during eachframe.
The line was temperaturecoloured:
• Yellow -very hot• Red -hot• &c.
This worked well in long shotsbut poorly in close up.
Computers in Film Making Slide 21
Ray Tracing Particles
More realistic rendering, includ-ing translucency, can be doneby ray tracing the particles
• Particles are given a radius
• As the ray passes through aparticle sphere it takes onsome of its colour.
• Rays that miss all theparticles take on thebackground colour
• Rays that pass through a fewparticles mix their colour withthe background
Computers in Film Making Slide 22
Fluid Fires
More realistic modelling can beachieved by treating the fire asa fluid in motion.
• Flames are incandescentgasses in motion
• Fluid motion is described by adifferential equation namedthe Navier-Stokes Equation
• Numerical solutions can beused to find a velocity field
• Particles move at thevelocities defined in the field
Computers in Film Making Slide 23
Ocean Waves
Another fluid modellingproblem is how to createocean waves.
Surface tension and driv-ing forces need to bemodelled.
A current research prob-lem is how to make thembreak
Computers in Film Making Slide 24
Ocean Waves
Another fluid modellingproblem is how to createocean waves.
Surface tension and driv-ing forces need to bemodelled.
A current research prob-lem is how to make thembreak
Computers in Film Making Slide 25
In Summary
• Computers have been a major force in film makingfor forty years.
• Computer Scientists contribute to the industry inmany ways:
• Analysis of 3D geometry• Specialised Hardware Design (GPU)• Describing and constraining behaviour• &c
• The challenges to computer scientists are:• Achieving Visual Realism• Creating Natural Movements for Avatars• Modelling and Rendering Amorphous Objects
• There are many small hi-tech companies in the fieldwanting excellent computer science graduates.
Computers in Film Making Slide 26