Class #11
Learning Outline:
Shape Deformation:
non-uniform scale, global deformations
Learning Material:
Concept:
A sequence of key shapes can be
interpolated over time to produce
flexible body animation (Deformation)
Types:
 Vertex Displacement
 Coordinate Grid Deformation (2D
Grid, Polyline)
 Global Deformation
 Free-Form Deformation (FFD)
Morphing Types:
 Coordinate Grid Morphing
 Feature based Morphing
3D Shape Interpolation Types:
 Matching Topology
 Star-Shaped Polyhedra (kernel)
 Axial Slices
 Map to Sphere
 Recursive Subdivision
Graphic:
Class2-Anim03ObjDeform.avi
Class2-Anim03ObjBend
Class2-Anim06CollisionDetection3
Vertex Displacement
 Seed vertex
 Distance function
Sketch on board
mesh, seed vertex,
area of effect,
deformed vertices
Coordinate Grid Deformation
Sketch on board
mesh, ref grid,
world vertex
positions, local CS,
deformed mesh
2D Grid
 Local vs. Global coordinate system
 Adjusting grid vertices deforms spline
 Bilinear interpolation
Polyline
 Boundary lines
 Object vertex mapped to Polyline
segments
 Deformation of object based on initial
vertex positions relative to Polyline
segments
Global Deformation
 Based on local coordinate system,
along Z axis
 Examples: Taper, Twist, Bend
 Linear or cubic or higher order
interpolation
 Can be combined to produce
Compound Deformations
Animations:
Bend
Twist
Taper Scale
Squash
Class exercise:
For each animation, project groups are
to describe the effects in terms of:
 Vertices
 coordinate systems (x, y, z)
 equations
 time (frames or seconds)
 interpolation
Keep in mind your desired effects in
animation projects
Animations:
Bend
Twist
Taper Scale
Squash