Abstract: In 3D deformable modeling approaches based on FEM, inverted tetrahedral elements can cause undesired visual artifacts and the breakdown of the simulation. As inversion can never be avoided and sometimes is even the correct behavior of elements, there is a strong need for stable inversion handling. In this paper, we propose a novel method to resolve inverted elements which is motivated by previous work of Irving et al. [6]. In combination with an efficient handling of degenerated elements, our approach yields a stable simulation of arbitrary deformations. Although we focus on the corotational formulation of linear FEM, the method can be implemented within arbitrary constitutive models.