I think that I have an answer - at least it works in Cinema 4D for this issue. When IK is disabled, the Goal is parented as normal in the hierarchy and its rotations reflect that. When IK is enabled, the Goal is parented to the BODY and the rotations reflect that. In order to go from enabled to disabled rotation values, you must apply a rotation transform matrix that is constructed from all of the rotations from the part after the BODY (usually Hip) to the part just before the Goal in the hierarchy. This is applied to the rotation of the Goal.

C makes it easy to shoot yourself in the foot. C++ makes it harder, but when you do, you blow your whole leg off.

 -- Bjarne Stroustrup

Contact Me | Kuroyume's DevelopmentZone