Nowadays, the use of Computer-Aided Engineering (CAE) system in product design has become mainstream. However, the adopted process from Computer-Aided Design (CAD) product definition to numerical simulation could be further improved to avoid going backward to the CAD model for model modification. To this aim, we propose a generic mesh modification operator whose architecture is detailed in this paper. A new instance of this operator for filleting FE tetrahedral meshes is also proposed. The filleting operator works in two main steps. The external skin of the tetrahedral mesh is first deformed to round user-specified sharp edges. Then, in the filleting area, the positions of the inner nodes are relaxed to improve the aspect ratio of the mesh ...