I have been having a heck of a time figuring this out. If I create an automatic skeleton in Maya 2011 and humanik/characterize it and WANT TO BRING in a motionbuilder motion, how would I retarget that to my Maya 2011 new character? I have a lot of motionbuilder fbx motions I purchased but want to use them solely in characters I create Maya 2011 using the characterize tools in Maya 2011. Thanks for any information. :) p.s. Motionbuilder works so slowly on my Windows 7. I mean it crawls. I have read RECENT posts about this (why does Motionbuilder 2011 use up so much system resources?) Iam not the only one. System resources goes crazy and I cant work. When running Motionbuilder 2011 with Windows 7 or 7 64bbit check out your system resource meter. I have tried tweaking my video driver a million ways. And of course newest drivers. However, with Maya 2011 have no problems. I can do all kinds of things and my system resources stays low. So, I want to give up on Motionbuilder and use my motions that I have for Motionbuilder in Maya 2011. So, any help would sure be appreciated. :)

import or reference your maya character (I recommend referencing)
If he’s not already characterized, do so
If you do not already have a control rig, build one (click the button)
import your fbx
Go to your T-pose (if it’s just locators and you don’t have a t-pose frame, this could be an issue, but our animations are at T-pose at frame 0 just for this)
Characterize what you imported from the fbx
in the human ik window, select your fist humanIK character node. Select the secont one as a source. This will be under the retargetting tab