Hi Reno,nnThank you for your very thorough answer! It seems that the main takeaway from your response is that you feel changing the SOFT option from 0 to 2 is generally preferred over messing with the contact stiffness. I am aware of the fact that SOFT=1 or 2 is preferred when dissimilar meshes and/or material densities are involved in impact, but in this case, the mesh densities are very similar and the materials are fairly similar in nature (the sphere is aluminum oxide and the target is an aluminum alloy). Do you have any insight into why you feel SOFT=2 might better handle this seemingly basic contact and thus prevent the need to tune the SLSFAC value? Sincerely,nJacobn