ISO 10303-521-2003 PDF

Full title and description

Industrial automation systems and integration — Product data representation and exchange — Part 521: Application interpreted construct: Manifold subsurface. This part of ISO 10303 (STEP) defines an application‑interpreted construct for representing manifold subsurface topology and its relationship to associated 3D geometry, allowing connected face subsets, subfaces and subedges, open shells and unbounded geometry to be represented within STEP-based exchanges.

Abstract

ISO 10303-521:2003 specifies how integrated resources are interpreted to define shape representations that contain open shells made up of connected face subsets. It covers 3D geometry, advanced faces, mappings and geometric transformations, relationships between domains of topological objects, subfaces/subedges and use of topology to bound geometric entities. The original 2003 edition was later withdrawn and replaced by a revised edition in 2011.

General information

• Status: Withdrawn (revised by a 2011 edition).
• Publication date: March 2003 (Edition 1).
• Publisher: International Organization for Standardization (ISO), developed under ISO/TC 184/SC 4.
• ICS / categories: 25.040.40 (Product data representation and exchange / STEP family).
• Edition / version: Edition 1 (2003); withdrawn and superseded by ISO 10303-521:2011.
• Number of pages: 36 pages (Edition 1, 2003).

Key bibliographic and lifecycle information above is based on the ISO catalogue entry for ISO 10303-521.

Scope

This part of ISO 10303 defines an Application Interpreted Construct (AIC) to interpret the integrated resources required to represent manifold subsurface topology within STEP. The scope includes representation of open and closed shells, connected face subsets where a subset's domain can be part of another shell domain, identification of faces/edges as subfaces/subedges, unbounded geometry with topological boundaries, and the topology-to-geometry mappings and transformations needed to support these constructs in exchange scenarios. The 2003 edition established the AIM for these constructs; the work was later revised (2011) to address clarifications and updates.

Key topics and requirements

• Definition of manifold subsurface application interpreted construct (AIC) for STEP exchanges.
• Representation rules for open shells and connected face subsets.
• Identification and treatment of subfaces and subedges within topological domains.
• Mappings between topology and geometry, including geometric transformations and unbounded geometry handling.
• Interoperability requirements to allow implementers to construct conformant AIM/MIM usage for subsurface topology.

Typical use and users

Primary users are CAD/CAM/CAE implementers, systems integrators and organizations exchanging complex 3D product model data where detailed topological descriptions (open shells, subfaces, unbounded geometry) are required. Typical uses include advanced geometric modeling, feature-level data exchange between engineering applications, neutral-archive of complex solids with open/topologically nested shells, and implementers of STEP application protocols or modules that require manifold subsurface constructs. General STEP users and implementers will also reference this part when building or validating AIM/MIM subsets that include these topological constructs.

Related standards

This AIC is part of the ISO 10303 (STEP) family and depends on integrated resources and other STEP parts (IR and AP modules) for geometry, topology and data representation (EXPRESS/implementation methods such as Parts 11, 21, etc.). It is related to other STEP AICs and later APs that reuse or supersede older AP content; the 2003 edition was formally revised by ISO 10303-521:2011. For broader context, see the main ISO 10303 series (STEP) and related APs that address geometry/topology and product model exchange.

Keywords

STEP, ISO 10303, manifold subsurface, application interpreted construct, AIC, topology, subface, subedge, open shell, connected face subset, 3D geometry, geometric mapping.

FAQ

Q: What is this standard?

A: ISO 10303-521:2003 is Part 521 of the STEP family (ISO 10303), an Application Interpreted Construct that specifies how to represent manifold subsurface topology and its mapping to 3D geometry for data exchange. The 2003 edition has been withdrawn and a revised edition was published in 2011.

Q: What does it cover?

A: It covers representation and interpretation rules for connected face subsets, open shells, subfaces and subedges, mappings and geometric transformations, and handling of unbounded geometry where topology defines geometric boundaries. These rules enable consistent exchange of such constructs between STEP-conformant systems.

Q: Who typically uses it?

A: CAD/CAM/CAE software vendors, systems integrators, implementers of STEP application protocols and organizations needing neutral exchange or archival of complex topological/geometry data are the typical users. Engineers and data managers working with advanced solid modelling and topology-sensitive exchanges will reference this part.

Q: Is it current or superseded?

A: The 2003 edition is withdrawn. It was superseded by a revised edition published in 2011 (ISO 10303-521:2011). Users should refer to the later edition for the current normative content.

Q: Is it part of a series?

A: Yes. It is part of the ISO 10303 (STEP) series, which is a large modular family of standards for product data representation and exchange. Part 521 is an Application Interpreted Construct (500 series) within that modular structure.

Q: What are the key keywords?

A: STEP, manifold subsurface, AIC, topology, subface, subedge, open shell, connected face subset, 3D geometry, ISO 10303.