I just had an inquiry about our lack of support of per-joint rotational offsets. That is a skeleton joint with zero rotation always has the same rotational coordinate system as its parent. This implies.. * ...a skeleton with every rotation zeroed-out, every joint with share the world's rotational coordinate system. * ...a positive-z rotation around one elbow with not be symmetrical with the positive-z rotation around the other elbow. * ...SmartBody prefers unnatural, "rectilinear" default/"zero" postures so that bones lengths exist along a single axis (an arm segment is +/-X, a leg segment is -Y, etc.).
We've just run into this problem again when trying to import animation data from another project. I'm not happy with the results, and I'd like to discuss how to change the situation. Adding support for rotational offsets will help us do simple tasks like flipping an animation. It should also simplify asymetrical procedural controllers, like walk & point, as they will need less code to abstract or special case left and right sides. However, I think our support for multiple rotation types (Euler, quaternions, and swing-twist) will complicate the issue. Each rotation type will need its own offset format. It will also require we add support for these offsets to our existing procedural controllers (gaze in particular), and may break several prior assumptions, like our straight, vertical spine. This is not something we can jump on right away, but I believe it is a long standing issue we will need to address. Thoughts and comments are welcome. Anm ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ Smartbody-developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/smartbody-developer
