Geometry warning, bone is N degrees away from it’s roll axis

When you preparing your skeleton to export to MotionBuilder, You need to be sure that all your roll bones lies on their parent’s roll axis. What does it mean? To answer, look at the parent local axis direction. It must look at the roll bone’s child. It’s like you can create a line between parent and child bones of the roll bone and check if you roll bone lies on it. Roll bone just devide this line without any bends.

On the left – wrong roll bone position, on the right – good roll bone position

Another very important thing is to make it clear that your bones orientations are alined. Maya has very usefull command to do that – orient joints tool.

Maya Character, FBIK