enum    gm_space_type { space2d, space3d };

    template< typename T, gm_space_type space = space3d >
    class   glue_manager_base 
    {
    protected:
        typedef point3D<T>  point_type;
    };

    template< typename T, gm_space_type space = space2d >
    class   glue_manager_base 
    {
    protected:
        typedef point2D<T>  point_type;
    };