Resolving particle collisions is one of the major challenges in numerical simulation of real life phenomena, as they give rise to non-smooth dynamics. There are two major school of methods for handling problems with contacts; the first envelopes the bodies with a so called ‘soft layer’, which does not allow the particles to ever really touch each other. In the second, the interactions are resolved via complimentary models. This is the model we focus on in this project. We are currently trying to come up with better numerical methods for solving these problems.