CAD 3D Design

CAD 3D Design is the logical capability of modeling a product’s three-dimensional geometry — parts, assemblies, and their relationships — using parametric, feature-based, direct, or surface modeling techniques. It is the vendor-neutral capability that CAD systems like Siemens NX, CATIA, SolidWorks, and Creo implement.

What it covers

• Solid modeling (boundary representation, constructive solid geometry).
• Surface modeling (NURBS, class-A surfacing for consumer products).
• Parametric & feature-based modeling (sketches, constraints, history trees).
• Direct modeling (geometry edits without history).
• Assembly modeling — positioning parts in context via mates, joints, and constraints.
• Model-based definition (MBD) — 3D annotations replacing 2D drawings.

Standards

Geometry interchange and long-term archival rely on ISO 10303-242 (STEP AP242) and ISO 14306 (JT). Conformance is tracked as conforms-to relations on the corresponding Logical data object notes once authored.

Relationships (see sidebar)

• Supports the CAD Design process.
• Implemented by systems like Siemens NX.
• Closely related to CAD 2D Drafting, CAD Assembly, CAD Simulation (pending notes).