Chapter 6_ Computer Animation Types and Techniques

7/24/2019 Chapter 6_ Computer Animation Types and Techniques

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MULTIMEDIA TECHNOLOGY

COMPUTER ANIMATION

Dr. Zeeshan Bhatti

BSIT-III

Chapter 6

BY: DR. ZEESHAN BHATTI 1


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Animation is about bringing things to life

Moving something which can't move itself

a sequence of images that, when played one

after the other, make things move

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Lets start.


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Luxo Jr. (1986) is the first three-dimensional computer animated filmto be nominated for an Academy Award

examples
http://www.pixar.com/funstuff/sh_videodescrip.htmlhttp://www.pixar.com/funstuff/sh_videodescrip.html


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Which one do you prefer?

If a picture is worth a thousand words, thenanimation has got to be worth ten thousandwords or more

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Animation Issues

When evaluating an animation technique, thenmostly the following things are considered:

How fast can the images be generated?

How easy is it to control the appearance of the animation?How much human expertise is required to generate the animation?

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Note:

Different applications havedifferent requirements:Feature film animation is different frominteractive gaming animation

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History of Animation

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Earlier 19th century

Phenakistiscope was invented by Joseph Plateau.


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Earlier 19th centurycont

Zeotrope was invented by William George Homer.The drawings were placed inside the spinning drum.


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Eadweard Muybridge captured the sequences ofhuman and animal movement by setting up a bankof cameras.


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Bullet time scene in The Matrix used 120 still cameras.


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Flip book was first patented by John Barnes Linnet. A set ofsequential pictures flipped at a high speed creates the motion effect.


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Emile Reynaud was created a technology Praxinoscopeto project animated film that last for 15 minutes.


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Types of nimation


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Controlling characters humans / cartoon characters / animals

Using real human movements

Manually creating the movements


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Motion Capture Manual Key-Frame

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Animating the face by Motion capture data

Using musculoskeletal models


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Most of what sells the intended emotion in

the face is the eyes. Youre probably familiarwith the expression, the eyes are the windowsto the soul. In animation, this is true, as well.A poorly animated set of eyes can kill the

illusion of life in a character.

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Simulating the pedestrians in the streets How does one's movement affect those of the

others


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Simulating the movements of clotheswhen the body moves

i.e How the wind affects the shape of

cloth


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How the hair moves when the wind blows

Need to take into account the physical properties of the hair,

Collisions between the hair The lighting effects


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Simulating liquid, mud, fire, bubbles How to efficiently simulate the motion of the

fluids

How to control the fluids so that the

animator can get what s/he wants


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Animation Techniques

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Basic Animation TechniquesAnimation techniques are processes orprocedures which are used to bringing things tolife

There are different techniques used by theanimator

Cell Animation

Keyframe animation

Motion capture animation

Procedural animation

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Traditional animation

Cel Animation

Keyframe animation McCay (1914) created Gertie the Dinosourcartoon animation and showed at theatre.

Celluloid sheets Earl Hurd used the sheets to hold certain elementswhile animating the characters on another layers. Easier to captureonion skinning.


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Keyframe animation


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Celluloid sheets


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TRADITIONAL ANIMATIONCONT

Walt Disney first released a short cartoon film with audio entitledSteamboat Willie. The most popular character are Mickey Mouse,Donald Duck, Goofy and Minnie Mouse.


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TRADITIONAL ANIMATIONCONT

Warner Bros. Studios invented cartoon characters with differentaesthetic look like Bugs Bunny, Daffy Duck.


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Present animation Rostrum camera used to shot simple 2D animation. Suitable

use to make collage or cutout. The camera equipped with an adjustable camera mount fixed

to a base board with a lighting source.


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Present animationcont

Software/computers animation used to develop 2D and 3Danimation.

The drawings were scanned or drew into the computer and filledwith digital paint instead of being transferred to cels and then

coloured by hand. With computer animation, many animation techniques rises; 3D CGI

animation, tradigital animation, cel-shaded animation.


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2d and 3d animation


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3D to 2D

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Tradigital and cel-shaded


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Realistic Human Modeling

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Adding Texture and Color

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Final

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Present animationcont

Rotoscoping developed by Max Fleischer. The animation is tracedover the actual film footage of actors and scenery.

From the AVI movies, you can import into a frame stack, digitallydraw or paint each frame.


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Future animation

Computer software like Autodesk MAYAwhich have developed inAvatar where itdesigns the characters and environments,shoot the virtual production elements, andcreate the stunning visuals that appeared

on the screen.


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Future animationcont

Stereoscopic 3-D (S3D) production. S3D is a technique for creating orenhancing the illusion of depth in an image by presenting two offsetimages separately to the left and right eye of theviewer. these 2D offset images are then combined in the brain togive the perception of 3D depth.


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Keyframing

Traditional animation technique

Dependent on artist to generate key frames

Additional, inbetween frames are drawn automatically by computer

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Keyframing

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How are we going to interpolate?


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Keyframe animation

The original way to animate, and still the most commonform for animation

It is the process of generating images between selected

key framesBefore, animation is done by sketching the differentimages on paper

Now done with computers

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I l i


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Interpolation

Interpolation is the process of computing

intermediate values between known values e.g.between two frames

The in-between frames are interpolated from thekeyframes

Interpolating splines are smooth curves thatinterpolate their control points

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1

2

3Keyframes Animation


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Interpolation

Many parameters can be interpolated to generate animation

Simple interpolation techniques can only generate simpleinbetweens

More complicated inbetweening will require a morecomplicated model of animated object and simulation

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Interpolation

Strengths Animator has exacting control (Woodys face)

Weaknesses

Interpolation hooks must be simple and direct Time consuming and skill intensive

Difficult to reuse and adjust

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Frame-by-Frame Animationcont

Inbetween facial drawings


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Keyframe examples

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2 frames drawn by user

Inbetween frames generated by computer


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Final Animation


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Linear Interpolation

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Simple, but discontinuous velocity


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Nonlinear Interpolation

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Smooth ball trajectory and continuous velocity, but loss of timing


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Easing

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Adjust the timing of the inbetween frames. Can be automated

by adjusting the stepsize of parameter, t.

Ease-OutEase-In


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Style or

Accuracy?

Interpolating timecaptures accuracyof velocity

Squash and stretchreplaces motionblur stimuli andadds life-likeintent

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Traditional

Motivation

Ease-in andease-out is likesquash andstretch

Can weautomate theinbetweens forthese?

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The Illusion of Life, Disney Animation

Thomas and Johnson


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More squash and stretch

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Anticipation

and Staging Dont surprise the

audience

Direct theirattention to whats

important

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staging


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Follow Through

Audience likes to see resolution of action

Discontinuities are unsettling

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Combined

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Secondary Motion

Characters should exist in a real environment Extra movements should not detract

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Motion Capture Animation

Extract data from real-world people acting out ascene

Many techniques for getting the data:Optical take video and extract motion

Magnetic/Radio attach magnets, transponders and use sensors to getlocation

Mechanical methods of extracting motion (for small motions)

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Motion Capture Example

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Examples

Sports video games Madden Football

Many movie characters Phantom Menace

Cartoons

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Motion Capture Strengths

Exactly captures the motions of the actor Michael Jordans video game character will capture his style

Easy to capture data

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Motion Capture Weaknesses

Noise, noise, noise!

Magnetic system inteference

Visual system occlusions

Mechanical system mass

Tethered (wireless is available now)

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Aligning motion data with CG character Limb lengths

Idealized perfect joints

Reusing motion data Difficult to scale in size (must also scale in time)

Changing one part of motion

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Blending segments Motion clips are short (due to range and tethers)

Dynamic motion generation requires blending at run time

Difficult to manage smooth transition

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Movies

Animating Aliens

Retargeting Motion

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Examples

Inanimate video game objects GT Racer cars

Soapbox about why this is so cool

Special effects

Explosions, water, secondary motion Phantom Menace CG droids after they were cut in half

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Procedural Animation

Very general term for a technique that puts more complex algorithmsbehind the scenes

Technique attempts to consolidate artistic efforts in algorithms andheuristics

Allows for optimization and physical simulation

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Animation is generated by writing a programthat outputs the position/shape/whatever of thescene over time

Generally:

Program some rules for how the system will behaveChoose some initial conditions for the world

Run the program, maybe with user input to guide what happens

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Oscillation Inside the Phase of contact


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by Zeeshan Bhatti PhD)

Oscillation Outside the Phase of contact


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Advantage: Once you have the program, youcan get lots of motion

Disadvantage: The animation is generally hard

to control, which makes it hard to tell a storywith purely procedural means

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Procedural Animation Strengths

Animation can be generated on the fly

Dynamic response to user

Write-once, use-often

Algorithms provide accuracy and exhaustive search that animators

cannot

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Procedural Animation Weaknesses

Were not great at boiling human skill down to algorithms How do we move when juggling?

Difficult to generate

Expensive to compute

Difficult to force system to generate a particular solution Bicycles will fall down

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All these animation techniques are great,


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all green box

combined single shots

but when they are most useful is when they

are all used together
http://escience.anu.edu.au/lecture/cg/CGIntroduction/Data/matrix_bullettimewalkthru1.movhttp://escience.anu.edu.au/lecture/cg/CGIntroduction/Data/matrix_bullettimewalkthru2.movhttp://escience.anu.edu.au/lecture/cg/CGIntroduction/Data/matrix_bullettimewalkthru2.movhttp://escience.anu.edu.au/lecture/cg/CGIntroduction/Data/matrix_bullettimewalkthru1.movhttp://escience.anu.edu.au/lecture/cg/CGIntroduction/Data/matrix_bullettimewalkthru1.mov


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The final scene

Comparison b/w animation techniques
http://escience.anu.edu.au/lecture/cg/CGIntroduction/Data/matrix_bullettimewalkthru3.movhttp://escience.anu.edu.au/lecture/cg/CGIntroduction/Data/matrix_bullettimewalkthru3.mov


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Technique Control Time to Create Computation Cost

Key-Frame Excellent Poor Low

Motion

Capture

Good at time

of creation,

after that poor

Medium Medium

Procedural PoorPoor to create

programHigh

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Comparison b/w animation techniques


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Questions?


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THANK YOU!

Chapter 6_ Computer Animation Types and Techniques

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