Hi, I just found a problem with the contact behavior. As is shown in the video attached, the object penetrate into each other a lot no matter how I adjusted the solver parameters. Right now the timestep is 1e-3. I set solref =[2e-3, 3] and increased first two digits in solimp to [.995 .999 .001]. From the slow motion I didn't see much improvement in the negative contact. The object still penetrate a lot at the first couple of steps. The difference compared to low damping solref values is that the huge bounce back is gone. Any idea about how to fix such behavior? Thanks in advance!