Creates a half-space solid and stores it in the geometry modeler object. 

Returns the creation result code:

• eOk if the half-space solid was successfully created.
• eNullEntityPointer if the tool has the illegal type.
• eGeneralModelingFailure in other cases.

The method returns the eNullEntityPointer value when the geometry modeler body is equal to the NULL, or the surface that defines the side of the half-space is equal to the NULL.