Artwork of cars is a complicated thing considering you're basically interpreting a copyrighted design of a car designed by a manufacturer. If you throw a Chevy bowtie on the rendering or use a copyrighted name to make money, you're actually asking for a legal battle if someone wants to be a real jerk. I suppose most of the people at GM for or DaimlerChrysler that see our work are saying, "cool rendering, that really sheds a positive light on our product". They [probably] don't care to get a lawyer involved to squeeze money out of the people who help to generate excitement about their heritage or current product line.
As far as our artwork being copyrighted, yeah, it should be. As I said, it is an artistic interpretation of a product. Whether it's cars, toasters, lampshades or fine china. We design the composition, the perspective and lighting so that image becomes OUR work. It's no different than photography. You wouldn't copyright your face if a newspaper photographer took a picture of you and published it in the newspaper. You just sign a release waiver for your name, wait for the paper to come out and brag to all your friends and family [if it's a flattering picture of course].
I didn't hear about Kris' battle with the polish company, but they should have, at the very least, asked his permission. People call me all the time to display my renderings on their websites. I never turn them down and always thank them for asking first. I'm not stupid, I want my stuff everywhere as long as my signature stays on it.
Steve probably knows a hell of a lot more about copyrighting images than I ever will. Maybe he could clear this up. I try to stay as far away from the petty and complicated legal crap as possible.
Stuart: I've asked several of my past clients if I can post their renderings on my site or to make extra prints of it to sell. Granted, I usually change a couple details so it's not exactly their car.