I have created a control rig for a humanoid robot. I needed to use the FBIK solver for the arms because the shoulder is actually three joints, each with a single Degree of Freedom. I believe that FBIK is the only solver that allows you to lock the rotation on a per axis and per bone basis. It seems to work great, as you can see in the first part of the licked YouTube video. But, when I rotate rig in world space (both bones further up the chain and the effectors), the whole rig gets wacky and the locked rotations are no longer honored. This seems crazy, as there is no reason for the locked rotations to be in anything other than local space and there is no option to change it.
Does anyone have an idea why this is happening or what to do about it? I’m about to the point where I might have to dig into the source of the plugin (dread) to try to fix what is broken.
Here’s what the rig graph looks like:
