FABRIK hand pointing problem.

I’m using FABRIK for my VR hand pointing. But it won’t work correctly, the lower arm is rotating in an weird way.
Here is the video:

here is my fbx file:

I’m stuck in this problem for days, what could possibly go wrong?
I also tried TWO_BONE_IK , but the lower arm is still rotating incorrectly.
My engine version is UE4.12.4 with Hairworks integrated.
Thanks guys!

Animation BP setup:

Character BP setup:

I am having the exact same problem with the exact weird lower arm rotation as yours.
Would like to know the solution for this as well.

You could try the TwoBoneIK controller too since that should in theory work for arms and might go away.

There might be something to do with the bone orientations and it’s getting confused as to the up vector. I myself haven’t had perfect results with FABRIK yet.

Not sure it will solve anything, but have you tried converting your transform to local space, and then changing the Effector Transform Space to Local? Other than that, i can only say that using both the TwoBoneIK and FABRIK tend to give kinda random results, and i would personally go for a custom solution like IKinema or similar.