I am a rigger in a game dev team. We are having a issue with the facial rigs in the engine, where all the facial joints gets dragged into the origin when getting merged with other body parts.
So, we have a system where we merge different body parts with each other to create different characters. And all the parts use the same skeletal system. Before, we had a skeletal system without the facial joints and recently we tried to import a whole new skeletal with the facial joints and swap it with the old skeletal system that is currently in place. Everything gets imported properly and when looked at separately in the skeletal editor everything looks fine and all the joints work perfectly. But the problem occurs when we try to merge the different body meshes.
When we try to attach the torso mesh to the head mesh as a preview part in skeletal editor it works fine. But, when we try to attach the head mesh to the torso mesh, the dragging of the facial joints occur.
We have tried swapping the skeletal system manually, exporting the joints from Maya again using FBX 2016, re-importing all the animations with the new skeleton, but nothing seems to work.
I have attached the images of the skeletal hierarchy in Unreal, the problem that we are having, and the facial joints in Maya. We would very much appreciate the help from the community to find a solution to the problem. Is there anything that we are doing incorrectly or something that we should be trying that we haven’t yet?
We are using Maya 2018/2017 and Unreal Engine 4.16.
Thank you for help.