Chapter 4 of the IGES 5.3 specification defines each entity by a type number (Directory Entry field 1) and, for some, form numbers (field 15) that select an interpretation of the same parameters. This register lists every type in that chapter. A dagger (†) marks an entity the specification calls untested (its section 1.9): no implementation has proved it works, so files rarely contain it. The parameter data of the geometry entities is on the Geometry entities page; the others are not yet written up, see the overview’s “Not described” list. How a record is laid out is on the File structure page.
The specification groups the entities into curve and surface geometry, constructive solid geometry, boundary representation solids, annotation and structure. The type numbers follow that grouping: 100 to 148 curves, surfaces, points, transformations and finite element data; 150 to 168 CSG primitives; 180 to 184 Boolean trees and assemblies; 186 to 198 B-rep solids and analytic surfaces; 202 to 230 annotation; 300 to 322 definitions; 402 to 430 structure, properties and instances; 502 to 514 B-rep topology.
Curves, surfaces and transformations (0 to 148)
| Type | Entity | Forms | Notes |
|---|---|---|---|
| 0 | Null | – | May have zero parameter lines; a reader ignores it |
| 100 | Circular Arc | 0 | Counterclockwise from start to terminate point, in a plane parallel to XT, YT |
| 102 | Composite Curve | 0 | Ordered list of constituent curves |
| 104 | Conic Arc | 1 ellipse, 2 hyperbola, 3 parabola | Informational only; form 0 is deprecated |
| 106 | Copious Data | 1, 2, 3 | Points as x,y pairs with a common z (1), x,y,z triples (2) or x,y,z,i,j,k sextuples (3) |
| 106 | Linear Path | 11, 12, 13 | The same three layouts, as a polyline |
| 106 | Centreline | 20, 21 | The points describe a centreline display symbol drawn as segments between points 1–2, 3–4 and so on (IP = 1, an even number of points); the associated matrix maps the XT–YT plane to model space |
| 106 | Section | 31 to 38 | Section line patterns for materials (parallel lines, pairs, dashes, quadruples and so on, forms 31 to 38; IP = 1 only) |
| 106 | Witness Line | 40 | IP = 1, an odd number of points, at least 3 |
| 106 | Simple Closed Planar Curve | 63 | The same layouts as forms 1 to 3 |
| 108 | Plane | −1, 0, 1 | −1 bounded portion is a hole, 0 unbounded (pointer to the boundary curve is zero), 1 bounded portion is positive |
| 110 | Line | 0 bounded; 1 semi-bounded†, 2 unbounded† | Forms 1 and 2 are the added unbounded lines |
| 112 | Parametric Spline Curve | 0 | Piecewise polynomial |
| 114 | Parametric Spline Surface | 0 | Piecewise polynomial patches |
| 116 | Point | 0 | Optional display symbol through a subfigure |
| 118 | Ruled Surface | 0 equal arc length, 1 equal parameter | Between two rail curves |
| 120 | Surface of Revolution | 0 | Generatrix revolved about a line |
| 122 | Tabulated Cylinder | 0 | Directrix swept along a vector |
| 123 | Direction† | 0 | A direction ratio |
| 124 | Transformation Matrix | 0, 1, 10, 11, 12 | 0 right-handed, 1 left-handed; 10, 11 and 12 describe a Node’s displacement coordinate system as Cartesian, cylindrical and spherical |
| 125 | Flash | 0 referenced entity, 1 circular, 2 rectangle, 3 donut, 4 canoe | A flashed aperture shape |
| 126 | Rational B-Spline Curve | 0 by parameters, 1 line, 2 circular arc, 3 elliptical arc, 4 parabolic arc, 5 hyperbolic arc | NURBS |
| 128 | Rational B-Spline Surface | 0 by parameters, 1 plane, 2 right circular cylinder, 3 cone, 4 sphere, 5 torus, 6 surface of revolution, 7 tabulated cylinder, 8 ruled surface, 9 general quadric surface | NURBS surface |
| 130 | Offset Curve | 0 | Constant, linear or functional offset |
| 132 | Connect Point | 0 | Electrical or fluid connection point |
| 134 | Node | 0 | Finite element node |
| 136 | Finite Element | see specification | An element made of nodes, with a topology type number and a name |
| 138 | Nodal Displacement and Rotation | 0 | Displacements and rotations at nodes |
| 140 | Offset Surface | 0 | A surface offset by a distance along an indicator vector |
| 141 | Boundary | 0 | The boundary of a bounded surface, with model space and parameter space curves |
| 142 | Curve on a Parametric Surface | 0 | A curve with its surface-space and model-space forms |
| 143 | Bounded Surface | 0 | A surface with boundary entities |
| 144 | Trimmed (Parametric) Surface | 0 | A parametric surface with an outer and inner boundaries |
| 146 | Nodal Results† | see specification | Analysis results at nodes (Table 8 of the specification) |
| 148 | Element Results† | see specification | Analysis results at elements |
Solids and analytic surfaces (150 to 198)
| Type | Entity | Forms | Notes |
|---|---|---|---|
| 150 | Block | 0 | CSG primitive |
| 152 | Right Angular Wedge | 0 | CSG primitive |
| 154 | Right Circular Cylinder | 0 | CSG primitive |
| 156 | Right Circular Cone Frustum | 0 | CSG primitive |
| 158 | Sphere | 0 | CSG primitive |
| 160 | Torus | 0 | CSG primitive |
| 162 | Solid of Revolution | 0 open profile projected to the axis, 1 closed with a line | CSG primitive |
| 164 | Solid of Linear Extrusion | 0 | CSG primitive |
| 168 | Ellipsoid | 0 | CSG primitive |
| 180 | Boolean Tree | 0 operands are primitives, instances or trees; 1 at least one operand is a B-rep solid | Post-order list; operations 1 union, 2 intersection, 3 difference |
| 182 | Selected Component† | 0 | Picks one component of a Boolean tree with a point |
| 184 | Solid Assembly | 0 items are primitives, instances, trees or assemblies; 1 at least one is a B-rep solid | Items with their transformation matrices |
| 186 | Manifold Solid B-Rep Object† | 0 | Shell-based solid |
| 190 | Plane Surface† | 0 unparameterised, 1 parameterised | Analytic surface for B-rep solids |
| 192 | Right Circular Cylindrical Surface† | 0, 1 | The same two forms |
| 194 | Right Circular Conical Surface† | 0, 1 | The same two forms |
| 196 | Spherical Surface† | 0, 1 | The same two forms |
| 198 | Toroidal Surface† | 0, 1 | The same two forms |
The forms of types 192 to 198 are given in the specification’s tables for each surface; only the plane surface’s were read in full here.
Annotation (202 to 230)
| Type | Entity | Forms |
|---|---|---|
| 202 | Angular Dimension | 0 |
| 204 | Curve Dimension† | 0 |
| 206 | Diameter Dimension | 0 |
| 208 | Flag Note | 0 |
| 210 | General Label | 0 |
| 212 | General Note | 0 simple, 1 dual stack, 2 embedded font change, 3 superscript, 4 subscript, 5 superscript and subscript, 6 multiple stack left-justified, 7 centred, 8 right-justified, 100 simple fraction, 101 dual stack fraction, 102 embedded font change with double fraction, 105 superscript and subscript fraction |
| 213 | New General Note† | 0 |
| 214 | Leader (Arrow) | 1 wedge, 2 triangle, 3 filled triangle, 4 no arrowhead, 5 circle, 6 filled circle, 7 rectangle, 8 filled rectangle, 9 slash, 10 integral sign, 11 open triangle, 12 dimension origin |
| 216 | Linear Dimension | 0 undetermined, 1† diameter, 2† radius |
| 218 | Ordinate Dimension | 0 simple, 1† with a supplemental leader |
| 220 | Point Dimension | 0 |
| 222 | Radius Dimension | 0 simple, 1 with two leaders |
| 228 | General Symbol | 0 general symbol, 1† datum feature symbol, 2† datum target symbol, 3† feature control frame, 5001 to 9999† implementor-defined (valid forms are 0 to 3 and 5001 to 9999) |
| 230 | Sectioned Area | 0 standard crosshatching, 1† inverted crosshatching |
Definitions (300 to 322)
| Type | Entity | Forms |
|---|---|---|
| 302 | Associativity Definition | 5001 to 9999 (defines an implementor’s associativity) |
| 304 | Line Font Definition | 1 repeating template subfigure, 2 repeating visible–blank pattern |
| 306 | Macro Definition† | see specification (and the Macro instance, which has no type number of its own here) |
| 308 | Subfigure Definition | 0 |
| 310 | Text Font Definition | see specification |
| 312 | Text Display Template | see specification |
| 314 | Colour Definition | 0 |
| 316 | Units Data† | 0 |
| 320 | Network Subfigure Definition | 0 |
| 322 | Attribute Table Definition | 0, 1 and others, see specification |
Associativities, properties and instances (402 to 430)
| Type | Entity | Forms |
|---|---|---|
| 402 | Associativity Instance | 1 Group, 3 Views Visible, 4 Views Visible, Colour, Line Weight, 5 Entity Label Display, 7 Group Without Back Pointers, 9 Single Parent, 12 External Reference File Index, 13 Dimensioned Geometry, 14 Ordered Group with Back Pointers, 15 Ordered Group without Back Pointers, 16 Planar, 18 Flow, 19† Segmented Views Visible, 20† Piping Flow, 21† Dimensioned Geometry, 5001 to 9999 implementor-defined; obsolete forms 2 (External Logical Reference File Index), 6 (View List), 8 (Signal String), 10 (Text Node) and 11 (Connect Node) are in Appendix F |
| 404 | Drawing | see specification |
| 406 | Property | see the table below |
| 408 | Singular Subfigure Instance | 0 |
| 410 | View | 0 parallel view, 1† perspective view |
| 412 | Rectangular Array Subfigure Instance | 0 |
| 414 | Circular Array Subfigure Instance | 0 |
| 416 | External Reference | 0 single definition from the file, 1 whole file as one definition, 2 external logical reference, 3† and 4† replace a Subfigure Definition or Network Subfigure Definition by a native copy |
| 418 | Nodal Load/Constraint | see specification |
| 420 | Network Subfigure Instance | 0 |
| 422 | Attribute Table Instance | 0, 1 |
| 430 | Solid Instance | 0 solid is a primitive, instance, tree or assembly; 1 solid is a B-rep object |
Property forms (type 406)
| Form | Property | Form | Property |
|---|---|---|---|
| 1 | Definition Levels | 19† | Line Font |
| 2 | Region Restriction | 20† | Highlight |
| 3 | Level Function | 21† | Pick |
| 4 | Region Fill (obsolete, Appendix F) | 22† | Uniform Rectangular Grid |
| 5 | Line Widening | 23† | Associativity Group Type |
| 6 | Drilled Hole | 24† | Level to LEP Layer Map |
| 7 | Reference Designator | 25† | LEP Artwork Stackup |
| 8 | Pin Number | 26† | LEP Drilled Hole |
| 9 | Part Number | 27† | Generic Data |
| 10 | Hierarchy | 28† | Dimension Units |
| 11 | Tabular Data | 29† | Dimension Tolerance |
| 12 | External Reference File List | 30† | Dimension Display Data |
| 13 | Nominal Size | 31† | Basic Dimension |
| 14 | Flow Line Specification | 32† | Drawing Sheet Approval |
| 15 | Name | 33† | Drawing Sheet ID |
| 16 | Drawing Size | 34† | Underscore |
| 17 | Drawing Units | 35† | Overscore |
| 18† | Intercharacter Spacing | 36† | Closure |
B-rep topology (502 to 514)
| Type | Entity | Forms |
|---|---|---|
| 502 | Vertex† | 1 Vertex List |
| 504 | Edge† | 1 Edge List |
| 508 | Loop† | 0 |
| 510 | Face† | see specification |
| 514 | Shell† | 1 closed shell, 2 open shell |
Notes on this register
- Entries marked “see specification” are entities whose form numbers were not read in full for this page. Form 0 is the default and is shown for entities whose section I did not find a form table for; if the specification defines further forms for such an entity, this register does not yet list them.
- The type numbers and names come from the specification’s contents and entity sections. The index in Appendix L labels type 123 “Dimensioned Entity” where the contents and section 4.20 call it the Direction Entity; this page follows section 4.20.
- Implementor-defined entities are allowed (section 1.6.6), to archive data forms unique to one system. Forms 5001 to 9999 are used for implementor-defined associativities (types 302 and 402) and general symbols (type 228).
Sources
- Initial Graphics Exchange Specification, IGES 5.3 – U.S. Product Data Association, 1996; the table of contents, chapter 4 and Appendix L