Open collaborative design/Vast libraries of machines and components

With enough people feeling that the priciples of open source are worthwhile reasons to collaborate over designing physical objects then vast libraries of designs for everything from components and various sub-assemblies to complete artifacts, machines and large complex systems will emerge, freely available for anyone to download and make use of.

As in software, for components to be as widely re-usable in many different machine designs, they will need to be made as modular as possible. This will enable a huge reduction in duplication of effort and allow people to focus their efforts on creating new machines of increasing complexity, building on the work of others.

To aid the re-usability of components (and more complex parts) it would be very useful within the CAD software to be able specify the vital functions of the unit, so that it can easily be warped in scale or form to better fit being incorporated into new designs while still ensuring it does it job correctly.