ISO 10303-204-2002 PDF

Full title and description

Industrial automation systems and integration — Product data representation and exchange — Part 204: Application protocol: Mechanical design using boundary representation. This part of ISO 10303 (STEP) defines the information model and file implementation conventions needed to represent and exchange boundary-representation (B-rep) solid models used in mechanical design.

Abstract

ISO 10303-204:2002 specifies the use of integrated resources required to represent and exchange volume-based boundary representation (B-rep) solid models in a mechanical engineering design context. It describes an application reference environment, the data models for geometry and topology (including curves, surfaces and pcurves), product identification, simple presentation attributes, units and naming, and the assembly relationships required to exchange complete B-rep shape descriptions between CAD and related systems.

General information

• Status: Withdrawn (replaced by later STEP work / AP 242 family).
• Publication date: August 2002 (Edition 1, approved in August 2002).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 25.040.40 (Industrial process measurement and control).
• Edition / version: Edition 1 (2002).
• Number of pages: 258 pages (first edition).

Scope

This standard defines an application protocol for representing and exchanging mechanical design information using B-rep solid modelling. In scope are three types of B-rep models (faceted, elementary-surface B-rep, and sculptured-surface B-rep), curve and surface geometry (including pcurves), manifold topology, product identification, simple presentation attributes (colour, line style, line width), preservation of user-defined names, units and measures, and assemblies of parts and subassemblies. Out of scope are wireframe-only models, general surface-only or trimmed-curve/surface representations, non-manifold topology, dimensioning and tolerances, manufacturing-specific data, and advanced presentation features (fonts, multi-view layouts, symbols).

Key topics and requirements

• Definition and exchange of B-rep solid models (faceted, elementary, sculptured).
• Comprehensive geometric primitives: curves, surfaces and pcurves for parameter-space definitions.
• Manifold topological representations (faces, edges, vertices, shells, loops).
• Product identification and assembly structure to support part/subassembly relationships.
• Simple presentation attributes (colour, line-style, line-width) associated with models or model elements.
• Preservation of user-defined names and identifiers to support traceability.
• Units, measures and consistent dimensional information for geometric elements.
• Physical file implementation guidance to support STEP-file exchange of the defined models.

Typical use and users

AP 204 is intended for CAD vendors, systems integrators, mechanical design engineers, PLM/PDM implementers, and organizations needing neutral, vendor-independent exchange of B-rep solid models. Typical uses include CAD-to-CAD data exchange, archival of geometric product models, and interoperability between design, analysis and manufacturing preparation tools where B-rep geometry must be preserved.

Related standards

ISO 10303 is a multi-part family (STEP). Closely related parts include ISO 10303-11 (EXPRESS language), ISO 10303-21 (STEP-file clear text encoding), other APs such as AP 203 and AP 214 (mechanical/automotive APs), and the later AP 242 (Managed model-based 3D engineering) which consolidated and superseded several earlier APs including AP 204. Relevant application modules and abstract test suites in the 1000–3000 series provide supporting building blocks and tests for B-rep usage.

Keywords

ISO 10303, STEP, AP 204, boundary representation, B-rep, mechanical design, CAD data exchange, geometry, topology, pcurve, product data, STEP-file, AP 242

FAQ

Q: What is this standard?

A: ISO 10303-204:2002 is an Application Protocol (AP 204) in the ISO 10303 (STEP) family that specifies data models and exchange conventions for mechanical design using boundary representation (B-rep) solid modelling.

Q: What does it cover?

A: It covers representation and exchange of B-rep solid geometry and topology (faceted, elementary and sculptured B-reps), parameter-space curves (pcurves), product identification, simple presentation attributes, units and assembly structure, plus the file implementation needed for STEP exchanges.

Q: Who typically uses it?

A: CAD vendors, mechanical design engineers, PLM/PDM integrators, systems that perform CAD-to-CAD exchange, and organizations that require long-term archival or neutral transfer of B-rep geometry.

Q: Is it current or superseded?

A: The 2002 AP 204 edition has been withdrawn and its scope has been largely superseded by later STEP developments (notably the AP 242 work). Users should refer to the AP 242 family (Managed model-based 3D engineering) and current STEP modules for modern implementations.

Q: Is it part of a series?

A: Yes — it is one part of the ISO 10303 STEP series of standards, which is composed of many parts covering description methods, implementation methods, application protocols and supporting modules.

Q: What are the key keywords?

A: Boundary representation, B-rep, STEP, ISO 10303, AP 204, CAD data exchange, geometry, topology, pcurves, product data.