ISO 10303-514:1999

Overview

ISO 10303-514:1999 - part of the STEP family (ISO 10303) - defines an Application Interpreted Construct (AIC) for an Advanced Boundary Representation (advanced B‑rep) used in product data representation and exchange. This part specializes the generic geometric and topological resources of ISO 10303 to require explicit, unambiguous definitions of manifold solid B‑reps whose faces and edges use elementary or free‑form geometry. The standard includes an EXPRESS schema, conformance rules and informative EXPRESS‑G diagrams to support implementation.

Key topics and technical requirements

• Advanced B‑rep shape representation: a shape representation composed of one or more manifold solid B‑reps; faces and edges must be explicitly defined by elementary geometry, swept geometry or B‑spline geometry.
• Topology and bounding: enforces that all surfaces are bounded via associated advanced faces and that curves are bounded via topological edge curves; uses manifold solid B‑rep definitions to ensure correct topological behavior.
• Permitted geometry types: 3D geometry, B‑spline curves and surfaces, conics, elementary curves and surfaces, sculptured surfaces, swept surfaces, twisted curves, polylines, p‑curves, and unbounded geometry for parameter and definition spaces.
• Restrictions / out-of-scope: excludes general 2D geometry (except p‑curves in surface parameter space), bounded curves beyond polylines and B‑spline curves, and bounded surfaces other than B‑spline surfaces.
• Formal EXPRESS specification: provides an EXPRESS schema (aic_advanced_brep) with entity definitions and WHERE rules (examples: WR1–WR6) that constrain the items of the representation (manifold_solid_brep, mapped_item, axis2_placement_3d, etc.).
• Interoperability dependencies: explicitly references and reuses constructs from ISO 10303-42 (geometry & topology), ISO 10303-511 (topologically bounded surface / advanced face), ISO 10303-43 (representation structures) and others.

Practical applications and users

• Who uses it: CAD/CAM/CAE software developers, PLM and PDM implementers, neutral data exchange tool vendors, and standards teams implementing STEP APs or building translators between systems.
• Why it matters: ensures consistent, unambiguous exchange of complex solid models with explicit topology and advanced surface definitions - critical for interoperability across CAD systems, downstream manufacturing, simulation and long‑term archiving.
• Typical uses: implementing STEP‑based import/export, defining neutral model repositories, validating topology/geometry integrity during data exchange, and creating conformance test suites for advanced B‑rep models.

Related standards

• ISO 10303 (STEP) series - general framework
• ISO 10303-1 (overview & principles)
• ISO 10303-42 (geometric & topological representation)
• ISO 10303-43 (representation structures)
• ISO 10303-511 (topologically bounded surface / advanced face)

Keywords: ISO 10303-514, advanced boundary representation, advanced B‑rep, AIC, STEP, EXPRESS schema, manifold solid B‑rep, B‑spline, CAD data exchange, product data representation.