sgCGroup* sgBoolean::Sub(const sgC3DObject& aOb, const sgC3DObject& bOb)
Creates a group of objects by subtracting the second object from the first one, i.e. the objects with points lying on the first object but not on the second one.
aOb - first object,
bOb - second object.
Returns the pointer to a group of objects constructed by subtracting the second object from the first one. If the objects are not intersecting or in case of an internal error the function returns NULL.
An internal error may occur in case you call this function for the surfaces or solids with self-intersections (these solids may be constructed, for example, by a number of kinematic operations).
The function for correcting self-intersections of solids is planned in the next library version.