MREGIONDefine a material region from a set of surfaces by logically combining the surface names and region names. A material region may be removed from the geometry by specifying the release keyword.To define material rgion, the operator lt, le, gt, and ge are applied to previously defined surfaces according to the following rules.
le -- if the surface following is a volume then le means inside including the surface of the volume. If the surface is a plane or a sheet le means the space on the side of the plane or sheet opposite to the normal including the plane or sheet itself.
gt -- if the surface following is a volume then gt means outside not including the surface of the volume. If the surface is a plane or a sheet gt means the space on the same side of the plane or sheet as the normal not including the plane or sheet itself.
ge -- if the surface following is a volume then ge means outside including the surface of the volume. If the surface is a plane or a sheet ge means the space on the same side of the plane or sheet as the normal including the plane or sheet itself.
Defining a material region will cause the information associated with
this material region to be stored under the name of the
geometry of the current mesh object. Releasing the material region
will remove this information.