 Describes a plane. A plane is positioned in space with a coordinate system (a gp_Ax3 object), such that the plane is defined by the origin, "X Direction" and "Y Direction" of this coordinate system, which is the "local coordinate system" of the plane. The "main Direction" of the coordinate system is a vector normal to the plane. It gives the plane an implicit orientation such that the plane is said to be "direct", if the coordinate system is righthanded, or "indirect" in the other case. Note: when a gp_Pln plane is converted into a Geom_Plane plane, some implicit properties of its local coordinate system are used explicitly: More...
