It’s more difficult than expected.
- Fix shape creation
I’m using maya 2016 blendshape editor’s new “edit” feature. Suprisingly it doesn’t work for all types of blendshape node, which mean I have to prepare a parallel blendshape for fix shape creation.
- Delta shape extraction
I’m using the script extractDeltas by Brave Rabbit with minor modification. It does half of the job. Assigning delta shape manually could be very tedious too. I have to automate it too so that the user wont’t see any delta shape.
- Pose Space Deformer as shape target driver
An easier way is to use the method of locator driver with pointConstraint as in the character Ray. It works well with small rotation angle not bigger than 90. But I prefer a general solution with possible angle from 0 to 180, which work from elbow to any other parts. Thus I’m implementing one based on the texture-based PSD method by Harry Houghton. I still can’t avoid the euler rotation problem since PSD has to follow in some areas like wrist twisting. They could be solved in specific ways, either by aimConstraint or direct connection.
By the way, the Shape plugin by Brave Rabbit probably do all the work mentioned above. Anyway it’s very close. Automating the opposite side and implementing reusing features would take the final little extra thought.