``Issues in Distributed CAD''
Prof. Alvaro Vinacua
Polytechnic University of Catalonia, I.R.I.
Edifici Nexus 202, C. Gran Capita 2-4
E08034 Barcelona, Spain
E-mail: alvar@turing.upc.es
URL: http://www.lsi.upc.es/~alvar

The views expressed herein are cast from the point of view of CAD and CAGD technology, and are undoubtly colored.

As our resources grow, we are attempting and executing the design of ever more complex, intricate systems. In doing so, some aspects gain more and more relevance:

• Design over a wide geographic area: Some of the actors in the process may be located at distant spots.
• Concurrency: To shorten the time from conception to manufacturing, concurrency in the design becomes essential when dealing with ever larger projects.
• Multidisciplinary component: often very large, complex systems will involve many different areas of expertise in their conception and design. It brings about the need to address different views and intuitive user interfaces, but also to handle transparently mixes of data from diverse domains.

The problems we face may thus have partial solutions in different realms. Many current techniques become relevant, but possibly in a mix not addressed before. These include:

• Distributed Databases
• Metadata
• Standard Data Interchange Formats
• Distributed Applications
• Networking
• Data Compression Techniques (and {\em ad hoc} data compression, tuned for certain kinds of data).
• Computer Supported Collaborative Work

Concerning the global sharing of geometrical and product data, many other specific aspects deserve attention:

• Data sharing. Over many years of development of CAD applications and after a widespread consolidation of CAD within the industry, this issue has shown large difficulty. A case may be made, even today, that it is still wide open. In any case present data interchange standards are not designed to share those models over large, probably slow, connections, nor are they geared to be easily accepted by applications from other domains. Standards supporting incremental transmission, partial model extraction and multiple views seem desirable.
• If effective collaboration and concurrent design are going to happen, we need to explore further mechanisms that allow the use of partial information without acquiring the whole model. Simple data interchange will just not suffice. It is unclear how far we may expect to go in this direction, and how feasible it may be to use this method in meshing with applications and data from other realms.
• Methods of partial publication of design data may allow companies to publish data to facilitate their customers the incorporation of their technology without compromising their own privileged information.