The Digital Preservation Coalition has released Preserving Computer-Aided Design (CAD).
Here's an excerpt:
Computer-Aided Design (CAD) systems are used in both industry and academia to create digital models, whether of engineering designs, archaeological dig sites, or virtual worlds. These models can be of long-lasting significance and importance, particularly if they contain irreplaceable data or relate to long-lived products. This report is primarily aimed at those responsible for archives and repositories with CAD content, but may also be useful for creators of CAD content who want to make their models more amenable to preservation. It begins with an introduction to the historical development and basic concepts of CAD systems, then reviews the most pertinent issues associated with preserving CAD models, and indicates the current state of standardization work in the area. The report goes on to present some recent research of relevance to preserving CAD models before drawing conclusions and making recommendations on how archives should handle the CAD models they accept.