The ConcaveMeshShape class can be used for a static concave triangular mesh.
It can be used to describe an environment for instance.
notes: it cannot be used with a dynamic body that is allowed to move. Moreover, make sure to use a ConcaveMeshShape only when you are not able to use a convex shape and also try to limit the number of triangles of that mesh because collision detection with ConcaveMeshShape is quite expensive compared to convex shapes.
r3d.ConcaveMeshShape.new creates a new collision concave mesh shape