This is a render from the Art Of Illusion 3D application.
Instead of using an image mapped onto a plane and inserted into a rendering that way, I decided to go ahead and make the model of the KDE logo itself. It still needs a bit of work (I need to make another gear with the teeth tweaked just a bit more...).
If anyone knows, or has tried to go the 'easy route' and simply locate an '8 tooth gear' model, THAT is not so easy. I finally gave up the search and decided to make the gear myself. Actually, it was easier to make the gear, than to locate one. It was just a matter of using a cylinder, 'tracing, a curve around the edge, making a tooth (cube), then using the array tool to place the desired number of teeth around that edge.
At any rate, I now have a 3D model of the KDE emblem for use in my renderings.
Yes, there are guidelines to it's use...
At the KDE Wiki are the artist guidelines. Simple, really... Just don't misrepresent the logo. That's about the gist of it.
KDE, K Desktop Environment and the KDE Logo are trademarks of KDE e.V