I know legal advice on the internet is worth what you paid for it, but I value GRM's collective opinion.
So, I just picked up a 2001 Caterham SV chassis that was involved in a car accident at some point. The frame itself is toast, but I'm going to use it to get the necessary dimensions to build myself a copy and use a Miata donor to make it go.
Where it gets sticky is, I'm going to make drawings/CAD models for myself, but can I distribute them in the public domain?
why not just look around online and see if someone else has already posted the same stuff? copyrights and patents mean nothing on the internet..
That's begging for trouble IMO, if you just make CAD models of Caterham parts and not only distribute them online, but try to make them public domain.
A really aggressively litigious company might try to sue you just for reproducing the parts for personal use...
cad drawings of caterham frames are already something you can get online... Check with the Locost USA forums.
I have a friend who makes truck equipment. He bought plans for dump truck bodies from a Russian company who had bought them from a now bankrupt Canadian Company. He was sued by a competitor who had purchased the Canadian assets of the original manufacturer even though everything was legal as far as he knew. The settlement was turning over all his truck bodies to his competitor and coming up with a new design with significant changes. The whole thing was pretty painful.
I guess the lesson is that there are lots of ways to be sued if you sell another persons ideas.
I think I've seen this project on the locost USA forum. 
in what ways does the frame differ from other "public domain" locost frames? If all you are doing is making a 3D model of the frame and posting it, but not selling it or making money I don't see the issue myself.
bgkast wrote: If all you are doing is making a 3D model of the frame and posting it, but not selling it or making money I don't see the issue myself.
IF it's the same as the "public domain" locost frame.
I should have included some background for the people who are less familiar with the Locost vs. Lotus vs Caterham.
No 3d models or comprehensive 2d cross sections are available for the Caterham SV. There are plenty of drawings/models for Locost frames. Drawings and models exist for the Lotus 7 Series 2. The Caterham SV is very similar to the Lotus 7, except it's wider, longer, slightly taller, but keeps all the original proprtions as the 7 that the Locost doesn't quite get right out of the box.
How is measuring a wrecked frame going to help? Seems like it would be off in some critical dimensions. Doing it for your own personal use is unlikely to get you into trouble; where you'll cause problems for yourself is in the distribution.
Hint: there are many ways to anonymize data files and to post them from anonymous locations like public wifi. Not that I would suggest doing such a thing.
In reply to Brotus7:
Isn't the Caterham chassis also heavily optimized and uses like 10 different tubes of varying thickness and size rather than 2?
My frame is wrecked, but not badly. The only reason I'm not using it is because I'd have to rebuild the transmission tunnel to fit the Miata in addition replacing the few bent tubes and cracked welds.
The frame is siginifcantly optimized over the early versions. Several different tube OD's and I'm going to do exploratory surgery for ID's.
As a general rule, reverse engineering something unless it's patent protected is going to be fair game. And it seems unlikely a Caterham frame would be original enough to be patentable.
Posting the files and making the files themselves public domain doesn't seem like it would be an issue. Making physical objects? Probably only trouble if they infringe on a patent.
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