4th Generation Design (4GD) is a new kind of collaborative design software that you can use to author and manage complex product designs, even designs consisting of millions of parts, such as for products created by the automotive and shipbuilding industries.
Prior to 4GD, designers often were limited to working with a single, predetermined, top-down assembly structure. 4GD introduces a more flexible paradigm for working with product data, where you can pull together ad-hoc collections of structure to fit any design task. 4GD designers can also modify any of the parts that comprise an overall design, without locking the
entire product or major assemblies.
Also, see the 4th Generation Design Guide within the Teamcenter Help Collection, as it contains a wealth of information on 4GD, including detailed descriptions of business processes and roles, use cases, and (best of all) even more videos.