We propose a straightforward solution to include volumetric models in an interactive simulation of deformable objects using the Finite Element Method (FEM), working directly with the triangular mesh. Our approach avoids the problems caused by the generation of tetrahedral meshes such as instability, bad quality meshes or meshes that deteriorate the performance. We use a high-quality tetrahedral mesh and perform the mesh intersection algorithm with the surface mesh which can be simulated in a stable manner by employing the extended FEM (XFEM). In this research, we improve the mesh intersection method by adding robustness to simulate complex meshes. We also show how to implement user interactivity in real time. Moreover, in order to ease the development of complex applications using deformable objects we propose a simulation architecture that indicates how to implement our approach.