Post 23 - Arms: Wrist manipulator issues

 The arms are next to be rigged. These are rigged using another ikRP solver as it, like the leg requires something to influence the angle it bends at. I have made the arm by placing the ik solver from the shoulder to the beginning of the twist (forearm) joint. Then 'effector was then repositioned and snapped to the wrist. The effector is effectively the ik handle's pivot point. By doing this, the ik motion moves the arm as it should, but does not interfere with the twist bone (since the forearm is split into two bones). 

Next task was to create a wrist manipulator, which would be used to rotate the wrist and control the arm via a parented IK handle. However, I have come up against a problem. My model's arms are at a slight angle. The process of creating a zeroed out object (manipulator) is by performing a 'freeze transformation' This zeros out all translational and rotational information, whilst maintaining the objects position in space. This however resets the rotational values. As my model's arms are not completely straight, this process creates an unwanted change in its orientation.

The solution for this is as follows:

1) Create Nurbs circle at centre of world space (0,0,0) 
2) Create a group for it (name it zeroed out, or similar) 
3) Snap position and parent the group to the hand/wrist joint 
4) Zero out the transform info for the group 
5) Rotate the group as needed for it to be aligned with wrist orientation 
6) Unparent the group 

Doing this leaves the group with all the unwanted transform information. The original circle controller is now in the right place, has the correct orientation and is zeroed out. The link below shows this process. The original solution to this problem was found of a CG Society forum, which can be viewed using this LINK. (answer provided by Coyote12)



IK Arm clip - LINK

Wrist Manipulator Freeze Transformation solution clip - LINK