Ok, so I took a closer look at this problem. and I had to kind of come up with a bit of a round about way to make it work. When I looked at it last night, it was just real quick and the problem that prevented a simple setup is just that CAT doesn’t like being linked to a dummy and also control that dummy. It creates a dependency error, where with normal dummies, it does actually work.
So, anyway, I made this video to explain the problem a bit and show a working setup.
I will say with all this though, it also makes it a bit clearer why it’s better to keep your “game skeleton” separate from your animation rig. There will be other problems if you used twist bones and things like that. But it’s always easier to have a separate rig just for this reason, where you create these dependency loops to try and make things work within one skeleton hierarchy.
But anyway, take a look at that video and see if it makes sense to you and if you have any questions, please post them here.
I did actually do a full export test based on this setup, doing animation with root motion and it all functions properly. The only problem I see is with exporting the CAT rig, it doesn’t come out cleanly as “bones”. So when you try import the animation file, it doesn’t seem to recognize it as animation in UE4. I didn’t do a whole lot of testing with regards to this, but you can get the animation imported, it just doesn’t automatically see the correct format because CAT bones comes through as objects, not bones.