Motion capture systems have been widely used for human
or animal motion capture ( [13]-[ 15]). Kirk [16] automati
cally generates rigid skeletons from optical motion capture
systems by preserving a constant distance for each rigid
part. These algorithms assume that the distance between
markers on the same bone is invariant and cannot be directly
applied to non-rigid bodies, such as natural trees, because
the distance between markers is not invariant as the object
deforms.