# NAME

GDX_CONE - Conical Surface

# GENERAL DESCRIPTION

A GDX Conical Surface (GDX Cone) parametrically defines a right circular Cone using a point on the axis of the cone, the radius of the cone at that point, the cone semi-angle, an axis vector, and a reference vector.

# DDF SPECIFICATION

    entity 17:0   GDX_CONE   "Conical Surface" {

    double
    CENTER[3];

    double
    AXIS_VEC[3];

    double
    REF_VEC[3];

    double
    RADIUS;

    double
    ANGLE;

    double
    TOP_PARM;

    };

# FIELD DESCRIPTIONS

CENTER

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

AXIS_VEC

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

REF_VEC

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

RADIUS

The radius (R) of the GDX Cone.

ANGLE

The cone semi-angle, SEMI_ANG, in radians. The angle formed by the side of the cone and the axis vector.

TOP_PARM

This value is for internal use only. If a GDX Cone 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 Right Circular Conical Surface Entity (Type 194) and can be found in Appendix G.12 of The Initial Graphics Exchange Specification (IGES) Version 5.2.

# PARAMETRIC RANGE

The GDX Cone is defined over the following parametric range: 0.0 <= u <= MTH_2_PI -infinity <= v <= infinity

# IMPLICIT EQUATION

The GDX Cone has the following implicit equation: S(x,y,z) = x*x + y*y + - (R + z*tan(SEMI_ANG))*(R + z*tan(SEMI_ANG)) = 0

# RESTRICTIONS

The GDX Cone is subject to the following restrictions: R >= 0.0 0.0 < SEMI_ANG < MTH_HALF_PI