[URGENT QUESTION] Rigging Belly When Upper Leg Raises


#1

Hello everyone, I have came across a problem where I could not find a way to get good deformations when character lifts his leg, what would be your approach to get good results?

I have tried 2 hip bones to create U-like bend shape but whatever I do, this is the best result I could get.

I also tried pose space deformer and tied up to the forward rotation of leg but when I move leg forwards and sideways, that shape is still triggering and it is giving me that blendshape even when I rotate the leg sideways


#2

You can add a few belly joints and drive them using either a simple Driven Key. Or use distance node and a locator attached to his bone. And drive the lift of the belly based on that distance. I thought about maybe attaching locator to the vertex, but realized that it will likely create a cycle dependency which is not very good.

Could use muscle system as well, if it’s not for a game engine.


#3

I tried that but my problem is since hip joint can rotate in all axis, if I hook its rotateZ to drive the belly joint when its going forward, everything is okay but if I rotate it forwards + sideways my rotations are not predictable therefore rotations that drive my belly joint are doing awkward motions. Is there a way to read rotations properly?


#4

Use a RBF solver. Brave Rabit does have a free one.


#5

To add to @mudoglu reply there is an even more involved RBF setup you can use.