During the past decades the open source software community has been producing many extremely good products. Some of these are totally free, even for commercial applications. Created and maintained by thousands of enthusiasts, in teams and as individuals who almost never meet in real life, one can only admire the energy and effort that these people put in these projects without expecting anything in return. Linux is probably the first example that comes to mind, but there are many others. KiCad EDA (pronounce 'Ki' as 'Kee'), a cross platform electronics design automation (EDA) suite, is another.
3D viewing capabilities
According to Wikipedia the KiCad project was started in 1992 by Jean-Pierre Charras; my first experiences with it date back to 2003 or so. At the time it was usable, but not adapted to my day job. However, KiCad continued to evolve to become a professional grade schematics and PCB design tool with 3D viewing capabilities.
As happens with such successful community projects, many people contribute. In the case of KiCad contributions are mainly in the shape of component libraries and tutorials, but also functional extensions. As an example, the very serious Hardware and Timing team at the international nuclear research lab CERN offered the push and shove interactive router. My own contributions to KiCad are inexistent, only this short article really, that I use to spread The Word.
3D libraries for KiCad
You can find the official 3D-model libraries for KiCad at GitHub, but there are also users who publish their own.
Recently an Italian website, maintained by a certain Walter from Padua drew my attention. This website offers a very large 3D library of components for KiCad. Besides the libraries, the website also explains some techniques for designing nice 3D component models. If you have to design your own make sure to have a look.
If you know of other good libraries for KiCad, feel free to add them as a comment to this article.