ISO 10303-109:2004

Overview

ISO 10303-109:2004 is part of the ISO 10303 (STEP) family and defines an Integrated Application Resource for representing kinematic and geometric constraints in assembly models. The standard specifies resource constructs to capture detailed geometric relationships between assembly constituents, enabling consistent product data representation and exchange for assemblies where relative geometry and motion matter. The publication includes EXPRESS specifications to support implementation.

Key Topics

• Geometric relationships between constituents - constructs to represent how parts relate spatially within an assembly.
• Geometric constraints - formalization of constraints that control relative position and orientation between constituents.
• Association of shape aspect relationships with representations - linking shape aspects to their geometric representations.
• Instanced assembly feature relationship mapping - associating instanced assembly feature relationships with their representations.
• Representation at the geometric_representation_item level - encoding detailed geometric information using elements such as:
  • assembly geometric constraints
  • kinematics pair
  • kinematics path
• Fixed constituent (anchor) - identification and representation of the part that serves as the fixed reference or anchor in an assembly model.
• Scope exclusions - product structure configurations of assemblies and tolerance information are explicitly out of scope.

Applications

ISO 10303-109:2004 is intended for use wherever accurate representation of assembly kinematics and geometric constraints is required for data exchange and model interoperability:

• CAD/PLM integration - transferring assembly constraint and kinematic data between CAD systems and PLM platforms.
• Simulation and analysis - feeding kinematic definitions into motion simulation and multibody analysis tools.
• Robotics and automation - defining kinematic pairs/paths for robotic assembly planning and path generation.
• Manufacturing and assembly planning - verifying assembly motion, clearance checks and virtual assembly procedures.
• Digital twin and maintenance documentation - preserving constraint and kinematic information in product digital records.

Primary users include CAD/CAM/CAE developers, PLM integrators, systems engineers, robotics/automation engineers, and technical data managers focused on model-based definition and interoperable product data exchange.

Related Standards

• Part of the ISO 10303 (STEP) suite for product data representation and exchange.
• Typically used alongside other STEP application protocols and integrated resources (e.g., APs for CAD interoperability and product structure).
• EXPRESS schema files provided with the standard support consistent implementation and mapping.

Keywords: ISO 10303-109:2004, STEP, product data representation and exchange, kinematic constraints, geometric constraints, assembly models, geometric_representation_item, kinematics pair, kinematics path, integrated application resource.