A Plane object is used as an auxiliary geometric object to enable plane slices through structured and unstructured meshes, as described in the next section. Planes cannot be directly passed to a Graph object to be plotted; they can, however, be plotted if they are a plane Slice object. The two positional arguments used to instantiate a Plane are:
<normal>: the direction numbers of the normal to the plane. If both arguments are omitted, this defaults to the positive x axis.
<point>: coordinates of a point through which the plane passes. If this argument is omitted, then the origin is the default.
A Plane object's data is actually stored as the coefficients of the plane's equation.