US company Liquid Machines has developed software that enables owners of documents and CAD files to control who has access to them. The group announced the extension of a system already available for formats such as word-processed documents into 3D CAD models at the SolidWorks convention in January in California.

Liquid Machines' senior vice-president Ed Gaudet said that, unlike security programs that work on the transmission of a file, its system works "inside the native code" of the application.

The software encrypts the data within a file and then allows access or other rights such as copying or printing only to specified users within specified timeframes. Rights can be activated or withdrawn remotely at any time and can also be varied more subtly by giving rights to particular parts of a product or an assembly.

Gaudet said the system is geared to the demands of global collaborative working, where an OEM might want a range of suppliers to have access to a design for a period, but for unsuccessful bidders then to be switched off.

"Not every country has the same intellectual property laws and this is a way of ensuring a level playing field," Gaudet said.

The system can also be used to provide version control where people in different firms are working on a single design and to provide an audit trail of who did what to any file. Gaudet said that a benefit of the concept is that it tracks the activities of authorised users as well as preventing unauthorised actions.

As well as SolidWorks, Liquid Machines' software is also available for PTC's Windchill design software and for a range of Microsoft and Adobe applications, plus files with.txt,.gif,.jpg and.xml extensions.