I am pretty much a novice with Motionbuilder and am running into some issues try to retarget animations from a bone skeleton to a CS Biped one so I can use the motions on a Biped character. I tried what I thought would be the easy way and exported the motions as bvh. Unfortunately Biped didn’t like the naming convention. So I am trying to retarget the motions onto a Biped rig.

Everything works fine except the arms are crossing over the chest too much.  I attached an image that illustrated it… the large character is the source and the smaller one is the Biped characterized rig I am trying to get it onto. In my bone skeleton the clavs are linked to the top spine bone and not the nech as it is in Biped. I tried this with the clavs linked both ways and got the same results.

I’m pretty frustrated at the moment because I thought the whole point of MB was it’s ability to retarget motions using the Control Rig easily. Once it’s on the control rig then 2 control rigs should “talk” seamlessly as the control rig is the common link between 2 different skeletons.....or so I would have thought.

Any direction on this would be greatly appreciated. 

-John

	Attachment

make sure that the target rig (the biped skeleton was in a true T stance arms out to the side when it is characterized. (biped arms are down by default)

and then use the reach T to help make the hands match.

Brad Clark
Co-Founder: Rigging Dojo-Teaching the art and science of character rigging
Author: Inspired 3D Advanced Rigging
The Character Animator Toolkit for Motionbuilder :available now:

Aha! That was it. The Biped’s reference pose had his arms down about 45 degrees. Not at it’s side, but certainly not up in a T pose. So that gets things pretty close, but the left hand is still off a bit. I can get things lined up good enough by using the Reach T and Reach R sliders, but since I need to process 90+ motions this way I am not to keen on messing with sliders for each one.

Is there a way to automate this somehow or will I need to do each one by hand?

-John

Thanks Brad..... Now I am starting to see some of the power of Motionbuilder. ;-)