PMI Annotations

PMI Annotations are the non-geometric attributes — dimensions, GD&T, surface finish, materials, weld and assembly notes — embedded directly on a 3D CAD model so the model itself, rather than a 2D drawing, defines the part. Semantic PMI is machine-readable; presentation PMI is human-readable only.

What it covers

• Semantic PMI — annotations linked to model faces and edges with formal meaning, consumable by downstream automation.
• Presentation PMI — graphical text and symbols for human display.
• 3D views and capture organizing PMI for inspection, machining, and supplier hand-off.
• STEP AP242 export preserving PMI through neutral-format exchange.
• ASME Y14.41 governance of PMI display practices.

Relationships (see sidebar)

• Supports the Detailed Design, CAM Manufacturing Planning, and Supplier Development processes.
• Implemented by CAD systems including Siemens NX, Dassault CATIA, SolidWorks, PTC Creo, and Autodesk Inventor.
• Carries GD&T into Model-Based Definition datasets and exports through STEP AP242.