A CAD model component or CAD model assembly is represented in your PLM database by a Windchill object known as a CAD document. CAD documents can be used to build companion Windchill product structures with special associative links that enable you to keep them synchronized as development progresses. The building of these Windchill product structures can be achieved automatically when its companion CAD document is checked into Windchill, or manually upon demand. Like its CAD document companion, a Windchill product structure can represent a single component part, or an assembly comprised of multiple parts with a hierarchical organization.

Since the first release of Windchill Workgroup Manager, PTC has provided the ability to create and drive a Windchill product structure from a CAD structure (the CAD document). This methodology is referred to as CAD-driven (or bottom-up) design.

In Windchill release 10.0, PTC added the ability to create and drive a CAD structure from a Windchill product structure. This methodology is known as top-down design (TDD) and is considered a best practice with regard to concurrent design. Both of these methodologies are enabled using the associative relationships that you establish (either automatically or manually) between CAD documents and Windchill parts.

For more information about design methodologies that are supported in Windchill, see Introduction and Methodology Overview.