I know it’s not possible to set one hinge axis, but is it possible to fake it without a bunch of external locked track constraints? I’d really love to know, because I’m horribly inexperienced with the animation system.
I’m assuming you’re talking about an armature. Is this in an IK or FK chain? If it’s in an IK chain, you can limit rotations so it only rotates around a single axis. If it’s in an FK chain, you can use the transform properties (N-key) and simply turn off rotation for specific axes.
Of course, I could be misunderstanding your question.
Sorry, I mean when you set a bone to hinge.