Native geometries are those shapes that are offered by default in the Marilou physics simulator. These are the basic shapes shown here:
Unlike complex composed shapes, such as point-triangles, the simulator handles contact optimally (without effort) between native geometries. Therefore the best way to obtain stable and fast simulation performance is to use these geometries whenever possible.
Not all collision pairs are implemented in the underlying simulator. Please check the ODE documentation (see Collision matrix) for more details.