As might be apparent from my recent posts, I am evaluating the constraint systems of Blender. One snag I have hit is that I cannot seem to make a constraint rely on local settings rather than global ones. The main concern is Copy Rotation, which insists on copying the target’s GLOBAL rotation, as if setting the transform coordinates to ‘global’. I really need to know how to make such a constraint use LOCAL settings instead. The reason is simply that if I rotate an object’s parent, the object must rotate with it, and when I afterwards rotate the constaint target, the constrained object must rotate relative to its position as dictated by its rotated parent.
For example, if I rotate a finger joint at the knuckle to point the finger down, the whole finger must point down (see image 1). If there is a constraint on the next joint of the finger, however, it will stick out (see image 2).
Image 1
Image 2
A local constraint would not interfere with something that is moved or rotated by a parent; instead, if you rotate the constraint target, the constrained object would simply ‘add’ that rotation to itself, as a local change. In short, the finger would point down when the knuckle parent is rotated, and rotating the constraint target would make the next joint (which has the constraint on it) rotate by that amount in -addition- to what the parent has done to it.
If that does not make any sense, I can elaborate…:spin:
(on the Constraint panel. It should be visible by default with the constraint “exanded” … if not, LMB on the little arrow beside the Constraint type name “Copy Rotation” to expand the constraints properties.