Week 11 - Animation

Question 1

What is traditional cel-based animation?

Answer 1

All frames are drawings composed by multiple transparent layers (cel) and differ (slightly) from one frame to the next to create the illusion of motion

Question 2

What is stop-motion animation?

Answer 2

In stop motion the animation is created by moving characters and objects by small increments to create the illusion of movement

Question 3

What are Animation Variables known as?

Answer 3

Avars

Question 4

What is physics-based animation?

Answer 4

Assign physical properties to objects (mass, forces etc) and calculate motion from simulating physics (dynamics, collision)

Question 5

What are particle systems and flocking behaviour?

Answer 5

Allows modelling of complex motions as the simulation of a large number of simple particles

Particles are spawned, transformed and killed at each update according to physics rules

Flocking behaviours also implements particle awareness of neighbours in their dynamics

Question 6

What is the concept of key frames?

Answer 6

Motion is defined by specifying the scene only at specific instants, in-between frames are generated by interpolation

Question 7

What is the concept of morphing?

Answer 7

Morphing stores a deformed version of the mesh, and uses interpolation to calculate intermediate meshes

Question 8

What is morphing useful for?

Answer 8

Animating deformable surfaces that are not clearly tied to a skeleton

Question 9

What is rigging?

Answer 9

To control a mesh animation, a hierarchical skeletal structure (or rig) is created, with articulated joints and mesh vertices are attached to it. Each bone in the skeleton is connected to a parent bone

Question 10

What is the concept of forward kinematics?

Answer 10

Forward kinematics calculate the pose of a joint from its parents

Question 11

What is the concept of inverse kinematics?

Answer 11

Inverse kinematics calculate the skeleton parameters to bring a given joint to a specified pose

Question 12

What is skinning?

Answer 12

The process of defining how a model’s surface deforms according to changes in the skeletal poe

Question 13

What is the concept of the Uncanny Valley?

Answer 13

The (unproven) hypothesis that characters that look almost, but not quite, human cause feelings of revulsion

Question 14

What is the concept of motion capture?

Answer 14

The process of recording the movement of human actors for animating a computer model

Question 15

What is motion capture also known as?

Answer 15

Mocap

Question 16

How does motion capture work?

Answer 16

Multiple synchronised cameras viewing the subject from different angles

Reflective markers are placed at joint locations on the subject

A marker’s position is estimated by triangulating from all camera views

Finally, the skeleton is animated according to recorded motion

Question 17

How does markerless motion capture work?

Answer 17

The subject is recorded simultaneously from all angles, and the background is subtracted. The shape is then reconstructed in all 8 views and texture is collected from the images

Question 18

What do motion graphs represent?

Answer 18

Possible transactions between recorded motions