Hi, I have used MuJoCo for quite some time so far but I still felt a bit confused on the relationship between the contact behavior and solver parameters. I found that, in general, reduce the timestep and first number of solref gives more stiff contact. Increasing them will cause more object penetration. But I also found that the stiff contact cause a lot of instability when object colliding with each other. For example, an object dropped to the table will bounce back to a even higher level. What should I do if I want the object collision to be more damped while minimizing object penetration at the same time? Also, could anyone give a qualitative interpretation on the solver parameters? How would they affect the contact behavior? I couldn't really connect the dots by reading the documentations.