SKM 4200 Computer Animation Chapter 4: Animation (3D Computer Animation – Part 2)

SKM 4200 Computer Animation Chapter 4: Animation (3D Computer Animation – Part 2)

Transcript of SKM 4200 Computer Animation Chapter 4: Animation (3D Computer Animation – Part 2)

SKM 4200Computer Animation

Chapter 4: Animation(3D Computer Animation – Part 2)

Deformation Tool

• Important tool for modeling– A great way to mold your object without having to change the form of

each polygon

• Used to facilitate tasks such as making facial expressions (opening a mouth wide for the dentist to drill)

• Also useful for simpler tasks such as wilting flowers or a bouncing ball which flattens when it hits the ground

Deformation Tool

• Deforming tools basically move large numbers of vertices in specific ways to change the shape of a model

• Different applications might use different terms – a deforming tool might be called a modifier

• The principles remains the same• Soft Selection was covered in the earlier chapters, and can be

considered as a deforming method

Deformation Tool

• Morph Targets– Basically, you crate multiple key forms (or targets) – Then, you use tools (such as the Morpher modifier in 3dsMax) to

morph between these key forms• Normally, animators will create an original form (e.g. a neutral face, with the mouth

shut)• Then, this form is copied and modified accordingly forming a morph target

– Note however that morphing between targets is best done when all the forms have the same number of vertices

• A slider control is provided in most morphing modifier, allowing animators to control the level deformation

– Examples on Youtube•• (part-1)• (part-2)

Deformation Tool

• Example of morph targeting (the last two youtube video examples)

Part-1 Part-2

Deformation Tool

• Curve deformers– Used to bend a model (or part of it)– Based on a curve of the animator’s choice– Moving the curve will move the model/mesh

Deformation Tool

• Lattice– Used to deform whole surfaces– This means that the shape of the lattice effects the shape of the model– The good thing about lattices is that you models can be evenly

deformed, and the process can be repeated similarly without having to play around with the model/mesh itself

Deformation Tool

• Specialized Deformers– Many applications provide ready to use deformers

• Bend• Flare• Twist• Flex (like how you flex your biceps)• Bulge • Warp• Narrow• Etc.

Original model ---------------------------Deformed---------------------------

Deformation Tool• Soft Bodies

– Used as the basis for flexible object deformation– Is basically a mesh, separate from the model– The soft body basically copies the vertices from the model and these are

replaced by particles• Particles are interconnected virtual points within a mesh, that react to simulated

forces or even collisions (with other objects)• Particles are therefore suitable for hair that might collide with clothing or even with

the model owning the hair• Particles are sort of similar to lattices, only that they are dynamic in nature (controlled

by laws of physics). This makes the more realistic than manual keyframe animation

– Note that its best to create a soft body deformed, based on the model, by using low polygon meshes• This can make calculations easier and can prevent your computer from hanging!!!

– Also note that sometimes, you need to add constraints to avoid unnatural movements (morphs)

Deformation Tool

Example: The Blob --

Deformation Tool

• Skeletons and Muscles– The skeleton rig is responsible to

move models– Each point on the mesh surface is

attached to the skeleton rig• When the rig moves, the point moves

Hence the model moves!!!

– Muscles are simulated• They are normally special lattice

deformers being moved by the skeleton• Makes organic movement realistic

Deformation Tool

• Rigid Bodies– Some models or surfaces need to retain their shapes

during animation– Examples of objects are such as cars, robots, knives,

swords and a piece of hard wood – The shape remains the same, regardless of whether the

rigid body is composed of multiple parts (e.g. a robot)