1. A method for a computerized Finite Element Method (FEM) system, a Computer-Aided Design (CAD) system, or a Computer-Aided Engineering (CAE) system to fix a contact region, comprising: detecting the contact region within a simulated model, wherein detecting the contact region comprises grouping into the contact region, triangles that intersect with other triangles; determining a classification of the contact region in the model; selecting at least one of fixing the contact region by moving a node in the contact region, fixing the contact region by local modification, or fixing the contact region by Boolean operation; wherein fixing the contact region by the Boolean operation comprises fixing the contact region by the Boolean operation in response to determining that the contact region is more than two element layers deep inside another contact region; fixing, based on the classification determined, the contact region by a selected one of fixing the contact region by moving the node in the contact region, fixing the contact region by the local modification, or fixing the contact region by the Boolean operation; and creating a tetrahedral mesh after fixing the contact region.