I'm having a difficult time writing a skinned mesh exporter for Maya, although for once it's not Maya's API that's causing the problem. This'll be an API-free post.
I clearly don't have a good enough grasp of the theory behind skinning.
I'm not sure what information I should be exporting for my joints at the bind pose:
World-space matrix, Inverse world-space, Local-space ( bone space ), etc
I'm somewhat comfortable with the actual deformation of vertices at render-time; I've written some small skeletal animation prototypes using existing formats.
I'm not very clear on how to create the initial data.
I have a skeleton in a rest pose.
I have the mesh at that rest pose.
Do I store the rest pose bones local matrices, or do I recursively multiply them with their parents' matrices, and then store them?
Do I store the model-space (not bone-space) vertices of the rest pose, and call this the bind pose?
If not, how do I determine the bind pose coordinates?
Unforunately my employer has given me a week to implement this; third-party libraries and existing formats are out of the question.