An Introduction to Computer Animation Dr Ian Palmer Electronic Imaging & Media Communications...
-
date post
19-Dec-2015 -
Category
Documents
-
view
215 -
download
0
Transcript of An Introduction to Computer Animation Dr Ian Palmer Electronic Imaging & Media Communications...
An Introduction to Computer Animation
Dr Ian PalmerElectronic Imaging & Media
Communications DepartmentUniversity of Bradford
Outline
In the beginning Some computer graphics basics Digital animation in the entertainment
industry Special effects Animation
Today and the future
1
1979-20022
Early days
• Mid-nineteenth century: Zoetrope– Individual images on the
perimeter of a wheel– Wheel rotated and images
viewed through a fixed slot
• Turn of the century: Film– Allowed production
of individual frames– Winsor McKay’s
“Gertie the Dinosaur”
The birth of animation
• 1930’s: Walt Disney– Use of transparent cels to
produce layered images– Animation moves from
novelty to mass entertainment and art form
• 1930’s: Willis O’Brien– Stop-action model animation
in “King Kong” set a standard for special effects animation
Traditional animation
One hour of animation on film (24fps) requires 86,400 frames
If frames are generated one by one this is an enormous task
Key-framing was first used for feature length animation by Walt Disney ‘Master’ animators draw the key positions Less experience animators draw in-between frames
The use of computers
• 1970’s: First use of computers– New York Institute of Technology– 2D in-betweening– 3D in-betweening
• 1980-90’s: Advanced techniques– Motion capture– Dynamics and kinematics– Procedural and character systems
Some computer graphics basics
Computers must store models of objects to allow them to be animated.
Most models stored as a set of points that are connected together to form polygons, and then a number of polygons are connected to form a ‘mesh’
These object meshes can then be ‘moved’ through the 3D world - 3D animation
To show this on traditional displays (e.g. TV and film) a 2D picture has to be created of the 3D world - this is called rendering
All methods are based on some aspect of modelling the way light behaves
A common one is ray tracing which calculates how rays of light travel and are reflected from objects
Some computer graphics basics
Ray tracing
Animating
Once we have a way of creating objects and generating pictures of them, we need to animate them
We can key frame them in three dimensions
lw
First major example: Tron
1982: Disney produce a film which contains a substantial amount of computer generated imagery (15 minutes!)
Landmark in digital animation, but a commercial failure
3
After Tron
Digital animation retreated back into the research laboratory for the next few years
But another technique and landmark film hit the screens in 1982: The Wrath of Khan
Particle systems - a collection of small objects that combine to produce the desired effect
4
Particle system
• Some phenomena are made up of tiny particles, each of which is individually (virtually) invisible
• It is the combination of many thousands or millions of these particles that produces the effect
• Particle system is a collective name for the approach that attempts to approximate fire, smoke, etc. by producing a system of individual elements that collectively produce the desired effect
• There is no ‘surface’ as such (just as in a real fire the flames have no surface)
Meanwhile...
John Lasseter, inspired by Tron, was trying to convince Disney that digital animation was viable
Produced short animations, including the Oscar nominated Luxo Jnr (1986)
5
Back in the special effects department: The Abyss (1989)
Modelling of a fluid creature Modelling flexible bodies & reflections
Convinced John Cameron that SFX could play amajor part in a movie
6
1991: Terminator 2
Used similar techniques to The Abyss for many of the effects
Motion capture of actors Hollywood now
convinced - birth of the ‘SFX movie’
7
Motion capture
We can attach motion sensors to different parts of the body of an actor and then use the appropriate channels to drive the motion of parts of a character
When the actor moves, the character is driven in real time
1993: Jurassic Park
Behavourial modelling E.g. flocking of birds and animals
Each object must try and match the velocity of its neighbours whilst avoiding collisions and trying to remain close the the centre of the ‘flock’
Such animation makes the automated process of animated large numbers of (almost) identical objects much faster
8
1995: Toy Story
The first feature length digital animation (79 minutes) 114,240 frames 800,000 rendering hours 3.5 minutes a week produced on average
Example character: Buzz 34,846 lines of code 700 separate animation controls
Quality of Disney applied to a 3D world
9
1997: Titanic
Procedural modelling All modelling and animation is described by a
(usually text-based) scene file This is in a scene description language and is
usually created by using an interactive package initially but may be edited
The scene file contains procedures that define the animation, hence the name procedural modelling
10
1999: The Matrix
2001-3: Lord of the Rings
Combines state of the art techniques with older methods
Vast amount of special effects
Only now is it possible to create Tolkien’s vision
Today
Mass produced TV digital animation Starship Troupers, Max Steel, Excalibur…
Many SFX based movies (and many with little or no plot!)
Hugely successful CG movies: Finding Nemo the most successful animated film ever
Tools make it much easier to produce all kinds of computer animation...
11 & 12
Today & the Future
Driving forces are the film industry and the computer games industry
New tools and research are making the production process much easier
Complete virtual actors with autonomous behaviour