this is my implementation of rigged skin and muscle model,I use modified bone to driver the muscle shape,with driver I can implement any complex muscle shape change,If i only want to deform the skin I even don’t need a muscle model,just need to paint the modified bone weight map to the skin area you want to deform.
if you want make another modified bone, you can copy and paste the modified bone with driver to any part of body,and retarget the driver control target bone.
the method is using the rotation value of control bone to driver the scale of modified bone,in order to deform the muscle or skin.
skin muscle driver.zip (2.18 MB)
here are some of my animation demos that made for a company using this driver muscle: