Research & Study: Skin Weights

Here are a comparison by using different Maya smooth skin bind methods(default settings) to bind a character:

• Closest distance
• Ignores joint hierarchy
• Using distance between vertexes and joint to bind
• Causes inappropriate influences on nearby discontinuous area
• Over falloff covers inappropriate area
• Closest in hierarchy
• Joint influence is based on skeleton hierarchy
• Prevent inappropriate influences like closest distance method
• Over falloff covers inappropriate area
• Heat Map
• Polygon mesh only
• May fail when finding bad faces
• Long time calculate to generate influences
• Better falloff but a little bit rigid for organic rigging

Another comparison on complex shoulder part:

According to above comparison, none of the skin bind methods can provide 80-90% well-done skin influences. Less or more, they have different disadvantages. As well as, none of them provides interactive skin bind method, or easy and quick setup method, instead of traditional painting skin weights, which has already been using in over 20 years.

Maya also has Interactive Skin Bind, a good idea, but not good to use at all.

• Interactive Skin Bind
• Cannot be used on NURBS
• Not accurate at initial setup, also hard to get accurate result by adjusting its manipulator
• manipulator is not user-friendly, like hard to rotate or translate the manipulator
• Increase the influences by dragging or changing the size of interactive skin bind manipulator. The manipulator may affect to discontinuous area, like legs or fingers, and causes inappropriate influences
• Linear workflow with painting skin weights, which means user can use interactive skin bind to breakdown or initialize skin influences, then paint skin weights to get accurate result, but if goes back to use interactive skin bind manipulator to adjust the skin weights, user will lose what just painted skin weights.