Assignment 1 Motion Interpolation

1
Assignment 1Motion Interpolation

• Date 2006/9/28
• TA ???
• alvin_at_caig.cs.nctu.edu.tw
• EC 229B Ext 56676

2
Framework

• Load the sampled motion
• Read the offset.txt file
• Create a new motion for interpolation
• Copy keyframes from sampled motion to the new
  motion
• Interpolate with different schemes
• Writes back the interpolated motion

3
Requirements

• Catmull-Rom interpolation.
• Spherical linear interpolation.
• Bezier interpolation.
• A Report
• Comparison of linear and spline interpolation
• Comparison of different representation

4
Graph 1
5
Graph 2
6
Graph 3
7
Crucial Techniques

• Catmull-rom Interpolation
• q(t) 0.5 t3 t2 t 1 -1 3 -3 1
  p1 2 -5 4 -1 p2 -1 0 1 0
  p3 0 2 0 0 p4
• For the segment between the first and second
  keyframe, we let the p0 p1 the first keyframe.

8
Crucial Techniques

• Degree to Radius Transformation
• Be careful when transforming between
  representation.
• Vector Quaternion Normalization
• Handle for Root Translation
• De Casteljau Construction for Bezier Curves

9
Crucial Techniques

• Shorter Path Check
• If q1q2 gt 0, the path from q1 to q2 is shorter.
• If q1q2 lt 0, the path from q1 to q2 is shorter.
• Speed Control for Bezier Interpolation
• Truncating the end segments to one third their
  original length
• An Slerp(qn, an, 1/3)
• Bn1 Slerp(qn1, bn1, 1/3)
• an will closer to qn and bn1 closer to qnl

10
Grading

• Catmull-Rom interpolation
• 20
• Spherical linear interpolation
• 20
• Bezier interpolation
• 30
• Report
• 30
• Bonus
• Speed Control(Section 3.2.2) Ease-in, Ease-out
• 10
• Embed your code in Amc viewer
• 5