ISO 10303-42:2022
ISO 10303-42:2022
Status : Published


This document specifies the integrated generic resource constructs for geometric and topological representation.  The following are within the scope of this document:

The following are in the scope of the geometry schema:

  • definition of points, vectors, parametric curves and parametric surfaces;
  • definition of finite volumes with internal parametrisation;
  • definition of transformation operators;
  • points defined directly by their coordinate values or in terms of the parameters of an existing curve or surface;
  • definition of conic curves and elementary surfaces;
  • definition of curves defined on a parametric surface;
  • definition of general parametric spline curves, surfaces and volumes;
  • definition of locally refined spline curves, surfaces and volumes;
  • definition of point, curve and surface replicas;
  • definition of offset curves and surfaces;
  • definition of intersection curves.

The following are in the scope of the topology schema:

  • definition of the fundamental topological entities vertex, edge, and face, each with a specialised subtype to enable it to be associated with the geometry of a point, curve, or surface, respectively;
  • collections of the basic entities to form topological structures of path, loop and shell and constraints to ensure the integrity of these structures;
  • the association of faces with geometric volumes;
  • orientation of topological entities.

The following are in the scope of the geometric model schema:

  • data describing the precise geometric form of three-dimensional solid
  • objects;
  • constructive solid geometry (CSG) models;
  • CSG models in two-dimensional space;
  • definition of CSG primitives and half-spaces;
  • creation of solid models by sweeping operations;
  • manifold boundary representation (B-rep) models;
  • constraints to ensure the integrity of B-rep models;
  • surface models;
  • wireframe models;
  • geometric sets;
  • creation of a replica of a solid model in a new location;
  • tessellated geometry;
  • the association of tessellated geometry with exact geometry.

The following are in the scope of the scan data 3d shape model schema:

  • representation of a shape as a cloud of points produced by a scanning process.

The following are outside the scope of this document:

  • all other forms of procedurally defined curves and surfaces;
  • curves and surfaces which do not have a parametric form of representation;
  • any form of explicit representation of a ruled surface.

    NOTE    For a ruled surface the geometry is critically dependent upon the parametrisation of the boundary curves and the method of associating pairs of points on the two curves. A ruled surface with B-spline boundary curves can however be exactly represented by the B-spline surface entity.

  • spatial occupancy forms of solid models (such as octree models);
  • geometric tolerances;
  • implicit forms of representation in terms of features;
  • assemblies and mechanisms.

General information

  •  : Published
     : 2022-12
    : International Standard published [60.60]
  •  : 7
     : 11
  • ISO/TC 184/SC 4
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