This is exactly my question. I have blend shapes that are changing my character’s proportions. I have a way to calculate the updated joint positions based on the blend shape values. I need to enter some kind of “edit mode” to do that though, otherwise I get a double translation. An example would be that the blend shape makes the arm longer, but when I move the skeleton to the new correct location, it moves the hand out even further.
In 3d packages you can very easily edit bones by entering a kind of edit mode, for example in blender:
bpy.ops.object.mode_set(mode='EDIT')
# move the bone
bpy.ops.object.mode_set(mode='OBJECT')
A more hacky way to do it would be to remove skinning move the bones and then reapply the skinning.
Does anyone have any suggestions for how to do this? Or can anyone give a definitive “this is not possible” with proof?