Collisions bugs with high DoF robots

[wyhuai]

Hi, I find that the collisions cannot be handled correctly when facing a robot with many body parts (over 30 bodies), and training will cause the graphics memory to slowly grow, the calculation speed to slowly decrease, and eventually overflow.

For example, when I use a humanoid robot with 30 bodies, it works well. But when I add new bodies it will show the mentioned problem.