NAME
GDX Entity Overview
OVERVIEW OF GDX ENTITY DEFINITIONS
The GDX geometry and topology entities have been designed to facilitate neutral representation of the various geometric and topological entities used in CAD/CAM systems and data exchange standards. Further, the GDX entities and corresponding functions have been designed with considerations of efficiency and numeric stability.
GDX ENTITY CLASSIFICATIONS
Parametric Curve Entities
| GDX_CONIC | Parametric Conic Arc | |
| GDX_NURB_CURVE | General Rational B-Spline Curve | |
| GDX_ARC | Parametric Circular Arc | |
| GDX_SPLINE_CURVE | Parametric Spline Curve | |
| GDX_POLYLINE | Polyline Curve | |
| GDX_COMP_CURVE | Composite Curve | |
| GDX_OFFSET_CURVE | Offset Curve | |
| GDX_TRIM_CURVE | Trim Curve |
Parametric Surface Entities
| GDX_NURB_SURF | General Rational B-Spline Surface | |
| GDX_SPLINE_SURF | Parametric Spline Surface | |
| GDX_RULED_SURF | Ruled Surface | |
| GDX_REV_SURF | Revolved Surface | |
| GDX_EXT_SURF | Extruded Surface | |
| GDX_PLANE | Plane Surface | |
| GDX_CYLINDER | Cylindrical Surface | |
| GDX_CONE | Conical Surface | |
| GDX_SPHERE | Spherical Surface | |
| GDX_TORUS | Toroidal Surface | |
| GDX_OFFSET_SURF | Offset Surface | |
| GDX_RECT_TRIM_SURF | Rectangular Trimmed Surface |
Curve Bounded Surface Entities
| GDX_CURVE_BOUNDED_SURF | Curve Bounded Surface | |
| GDX_COMP_EDGE_CURVE | Composite Edge Curve | |
| GDX_EDGE_CURVE | Edge Curve |
Topology Entities
| GDX_SOLID | Solid | |
| GDX_SHELL | Shell | |
| GDX_FACE | Face | |
| GDX_LOOP | Loop | |
| GDX_EDGE | Edge | |
| GDX_EDGE_CURVE | Edge Curve | |
| GDX_VERTEX | Vertex |
Surface Approximation Entities
| GDX_CURVE_MESH | Curve Mesh Surface | |
| GDX_RECT_MESH | Rectangular Surface Point Mesh | |
| GDX_FACET_SHELL | Facet Shell Surface | |
| GDX_POLY_SHELL | Polygon Shell Surface |
GDX_MATRIX
The GDX GDX_ARC and GDX_CONIC entities contain a matrix field that corresponds to a GDX_MATRIX. GDX_MATRIX is a typedef provided by the gdx_Interface.h include file and is defined as follows: typedef double GDX_MATRIX[12];
The fields of the GDX_MATRIX are stored in the order as illustrated below:
| R00 R01 R02 | | Xinput | | Tx | | Xoutput | | R10 R11 R12 | | Yinput | + | Ty | = | Youtput | | R20 R21 R22 | | Zinput | | Tz | | Zoutput | GDX_MATRIX[0] = R00 GDX_MATRIX[1] = R01 GDX_MATRIX[2] = R02 GDX_MATRIX[3] = Tx GDX_MATRIX[4] = R00 GDX_MATRIX[5] = R11 GDX_MATRIX[6] = R12 GDX_MATRIX[7] = Ty GDX_MATRIX[8] = R20 GDX_MATRIX[9] = R21 GDX_MATRIX[10] = R22 GDX_MATRIX[11] = Tz