Split side.
The split operation parameter for specifying on which side
of the splitting element material in splitted element should be
removed.
Values:
catPositiveSide
Material in the splitted element should be removed in the direction
indicated by the splitting element normal vector. This vector is
oriented towards the outside of the material when a face is selected.
catNegativeSide
Material in the splitted element should be removed in the direction
opposite to the one indicated by the splitting element normal vector