Rob Chapman

Oh! it seems the add animation from skeleton node fails on more complex nested rigs.. like the metahuman head skeleton.

so still the simplest way to put fbx back onto the head rigs at least is to unpack and repack and animation from skeleton works on body still

Ahah ! it was the mapping and trial and error, but indeed this is the node you need , thank you and once correctly setup it all lines up nicely and animates directly from the FBX animation file - which includes skeleton animation and shapes
just finishing off the blendshape mapping list - theres a LOT of remapping and its changed again since you wrote the last snippet Edward, Brow name did at least

edward
The process is complicated because we need to do "rig inversion" here. From the world space transforms of the joints, deduce the controller transforms necessary to achieve the same result. Rig Copy Transforms should work but it might screw up if the rest poses are not accurate because it copies them relative to the rest poses on the skeletons. It gets progressively harder beyond IK rigs, and esp. if you have rigs that use abstract controllers for IK/FK switching because you need knowledge of how the rig works in order to do this. For the next major release, we have an HDA that wraps a similar set up to help ease this common problem. But it's tricky so it's not foolproof.

If you have an example can submit an RFE with your files, we can give it a try with our HDA to see if can work.

is this HDA inside houdini 21? whats it called?

it does seem rather complicated to rig match pose and all the other bits mentioned justto map the animation from an FBX onto the EXACT same skeleton, but im new to Apex and hopefully this will improve?, Ive got the shapes working in metahuman finally, (from your helpful Python snippet in another thread) but I guess these shape values can transfer straightraway easier than world space rig pose bone matching...