By way of a "direction arrow" (comparable to a "slope arrow" on a floor), the direction of a material kan be determined.
For example, a large floor is divided in parts. The material for each part needs to be aligned with the walls, which are set at random angles.
Currently, each floor-part, needs to have a different material assigned to it (be it in the floor-type, or by paint. By being able to set the direction per surface-instance, No more than one floor-type and one material are needed.
This would be instance based information.
Applications on floors, walls and roofs would be useful.