Quick Question: Do IK and FK rigs in the game engine

I heard a long time ago (two or three years ago) that they don’t work in the game engine. Has that changed? I’m also wondering what effect it has on the engine. Does it slow it down significantly? I want to know this before I spend a couple of hours learning how to apply this.

Thanks a lot!

What is FK?

IK I know that I (and other constraints) work very well.
not easy to make an armor that works with many constraints, but when the armor is made, these allow you to use a few keyframes and then in my opinion are very efficient.
Besides being very comfortable. You can do a complex action in few minutes

FK is forward kinematics:
It’s just a standard rig where you rotate one bone and whatever bone is a hierarchy of any other bone it follows

Yes they both work in the game engine: IK and FK

thanks a lot guys!