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Requirements Capture

AP 210 captures design requirements that constrain and validate the physical design. This includes geometric tolerances, dimensional constraints, material specifications, and functional requirements.

Types of Requirements

AP 210 models several categories of requirements:

Geometric Requirements

  • Dimensional tolerances - Acceptable variation in linear and angular dimensions

  • Geometric tolerances - GD&T specifications (flatness, parallelism, position, etc.)

  • Surface finish - Acceptable surface roughness

  • Clearance requirements - Minimum distances between features

Physical Requirements

  • Material specifications - Required material properties

  • Thermal requirements - Maximum operating temperatures, thermal resistance

  • Electrical requirements - Voltage ratings, current capacity

  • Environmental requirements - Humidity, vibration, shock tolerance

Design Constraints

  • Keepout zones - Areas where features cannot be placed

  • Minimum spacing - Minimum distances between features

  • Maximum trace length - Signal integrity constraints

  • Impedance control - Controlled impedance trace requirements

Requirements in the Model

Requirements are linked to the design through:

  • product_definition_relationship - Links requirement to design

  • characterized_representation - Properties associated with shapes

  • shape_aspect - Specific features on a shape with requirements

Example: ATX Envelope

The ATX motherboard specification defines:

  • Maximum board dimensions (305mm x 244mm)

  • Mounting hole locations

  • Connector placement zones

  • Component height restrictions

  • Keepout areas around CPU socket

Each of these can be captured as AP 210 requirement entities linked to the board definition.