# NAME

GDX_PLANE - Plane Surface

# GENERAL DESCRIPTION

A GDX Plane Surface (GDX Plane) parametrically defines a plane using a point on the plane, normal vector, and reference vector.

# DDF SPECIFICATION

    entity 15:0   GDX_PLANE   "Plane Surface" {

    double
    CENTER[3];

    double
    AXIS_VEC[3];

    double
    REF_VEC[3];

    double
    U_PARM;

    double
    V_PARM;

    };

# FIELD DESCRIPTIONS

CENTER

A 3D array containing the X, Y, and Z coordinates of a point on the GDX Plane.

AXIS_VEC

A 3D array representing the unitized normal direction of the GDX Plane. Corresponds to the z direction in the parameterization of the GDX Plane.

REF_VEC

A 3D array representing the unitized reference direction of the GDX Plane. Corresponds to the x direction in the parameterization of the GDX Plane. This vector should be perpendicular to the AXIS_VEC.

U_PARM

This value is for internal use only. If a GDX Plane Surface entity is created without using functions in the gcr subsystem, this value should be set to -1 (indicates the entity is not locally bound).

V_PARM

This value is for internal use only. If a GDX Plane Surface entity is created without using functions in the gcr subsystem, this value should be set to -1 (indicates the entity is not locally bound).

# PARAMETERIZATION

The parameterization is the same as that used for the IGES Plane Surface Entity (Type 190) and can be found in Appendix G.10 of The Initial Graphics Exchange Specification (IGES) Version 5.2.

# PARAMETRIC RANGE

The GDX Plane is defined over the following parametric range: -infinity <= u <= infinity -infinity <= v <= infinity

# IMPLICIT EQUATION

The GDX Plane has the following implicit equation: S(x,y,z) = L * x + M * y + N * z - (x0 * L + y0 * M + z0 * N) = 0

       where L, M, and N are x, y, and z coordinates of normal vector
       and x0, y0, and z0 are coordinates of a point on the plane.

# RESTRICTIONS

None.