Discrepancy between bone rotation in Motionbuilder and UE4

In motionbuilder the right hand has a global rotation that points directly forward.(In global rotation right below the view)

If i add a socket to that hand in UE4 that socket is slightly rotated

Neither the gun nor the socket have any rotation

I plotted everything to the skeleton

This is the fbx file:

FBX file

Motionbuilder uses fbx as format.

Thanks for posting the file!

So I found the issue. Didn’t have to go into Unreal – this is a Skeleton issue.

So in the skeleton of the character, the wrist joint is oriented different than the Mobu controller. I’ve attached a pic from Maya of the baked skeleton.

You’ll see the wrist bone’s orientation is off center, even though the wrist is visually pointed forward. Rather than messing around with this offset value in Unreal (trying to fudge perfect value for the weapon), I would highly recommend making an ‘attachment’ bone off of the wrist for just this purpose. You’ll have fine control over the weapon placement and get it just right. It’s super handy down the line if you ever want to animate the weapon flying out of the hands too (or any other crazy moves like that).

Image

Thanks I have seen the issue too now.

I fixed it now already and it works as intended.

It is attached to a socket but i usually want to understand why exactly the things behave the way they do so i have absolute control over what i do

the difference comes from the control rig that doesn’t have exactly the same rotations as the skeleton

Thanks for the time.

Cool, glad it helped! If this is solved feel free to mark it answered so it can be closed out