@Veratai
Actually, I tested the same structure on the elbows to see if I could get a more elbow-like feel, but it seemed like there would be problems when twisting them, so for now I'm only using it on the legs.
I think Vroid has problems with the topology and bone placement, which is why the weights are strange...
hm.. wonder if the elbows require a similar treatment.. they too get somewhat 'wrong' in deep arm bend poses, or twists
but vroid is full of those micro-issues with weights
@Veratai
Yes, that's the structure I used. I think this shape is ideal for expressing the rotation of the kneecap and the double joint when the knee joint is bent, with a simple structure.