Skeleton structure
Characteristics
- - Hierarchical representation
-
- All children follow the transformation of the parent
- Need to define a root: usually at the hips/pelvis
- - Convenient to express local deformation with respect to the parent
-
- ex. Rotate knee from \(20^{\circ}\)
Converting local to global frames/joint coordinates
- With 4x4 matrices \(M\)
- With translation \(t\), rotation \(R\)
- \(M^i_{global} = M^{i-1}_{global}\;M^{i}_{local}\)
- \(R^i_{global} = R^{i-1}_{global}\;R^{i}_{local}\)
- \(t^i_{global} = t^{i-1}_{global}+ R^{i-1}_{global}\,t^{i}_{local}\)
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