We present two robust and direct algorithms or both voxelization and polygonization of solids constructed as Boolean combinations of free-form solids (free-form CSG solids). These algorithms are based on Extended Simplicial Chain (ESC ) model; they are robust as they are fully based on a point in solid test (derived from ESC model) that does not need either solving equation systems or dealing with complex special cases. Final results are directly obtained from CSG expression, without evaluating Boolean operations. Both algorithms have been developed by looking for an agreement between the result precision and the computation cost.