ISO 10303-55:2005

Overview

ISO 10303-55:2005 - part of the ISO 10303 (STEP) family - defines an integrated generic resource for the procedural and hybrid representation of product models. It specifies data constructs for representing models that are defined by their sequence of constructional operations (construction history), and for combining procedural descriptions with explicit geometric representations. The standard provides mechanisms to link to entity types defined in other ISO 10303 parts (representation_item types) and includes an EXPRESS schema for implementation.

Key topics and technical requirements

• Procedural (construction history) representation: defines resource constructs that capture sequences of constructional operations used to generate models.
• Hierarchical structuring: supports organization of construction sequences into hierarchical groups for modular and reusable procedural workflows.
• Hybrid representation: allows embedding explicitly defined elements (explicit geometry or features) within procedural sequences to create hybrid models.
• Dual representation: enables associating a procedural model with an explicit “current result” model that represents a representative instance from the procedural/parametric family.
• Interoperability with other STEP parts: uses representation_item definitions and other entity data types from other ISO 10303 parts to represent operations and geometry; ISO 10303-55 itself does not define the operation entities.
• Design rationale and selection metadata: supports attaching design rationale to procedural models and identifying explicit elements picked interactively from visual displays.
• Model simplification controls: identifies constructional operations that can be suppressed to create simplified model variants.
• Specialization for shape models: includes capabilities targeted at procedural representation of shape/geometry models.
• Implementation artifact: an EXPRESS schema is provided to facilitate implementation of the resource.

Applications

• CAD/CAM/CAE data exchange where construction history or procedural definitions must be preserved across systems.
• PLM and digital manufacturing workflows that need hybrid models combining parametric procedures with explicit geometry.
• Model simplification, versioning, and downstream consumption for simulation, visualization, or manufacturing.
• Archival and reuse of design intent, including associated design rationale and interactive selections.

Who should use this standard

• CAD/PLM software developers and integrators implementing STEP import/export.
• Systems engineers and digital manufacturing specialists who manage procedural/parametric models.
• OEMs, suppliers, and standards bodies aiming for robust product data interoperability.

Related standards

• ISO 10303 (STEP) family - general framework for product data representation and exchange.
• Other ISO 10303 parts specifying specific representation_item entity types and geometry/feature definitions.

Keywords: ISO 10303-55:2005, STEP Part 55, procedural representation, hybrid representation, product data representation, EXPRESS schema, construction history, CAD, PLM.