I had an idea for how to make a certain product much better. I'm currently in the prototyping stage for a product based on that idea. That idea (the solution to the problem of improving that product in certain ways) is patentable according to all the stuff I read about patents. But patents are really expensive: My primary market would be western Europe (member states of the European Patent Convention) and possibly later the US, that would cost a 4-digit USD amount upfront and in total a 5-digit amount within a couple of years, as far as I can tell.
So I'm evaluating the possibility of just keeping my invention secret until I'm ready to sell a product based on it and then publishing the full details to make sure no one else can patent it.
But when I'm selling such a product: Would competitors need to design a new product based on my idea, involving all the prototyping and too easy to patent but still not trivial problems - or would it be legal to take my product apart, put the parts in a 3D scanner and produce the exact same product? Where is the border between what is allowed and what not, exactly?
Say I found a new method to make car chassis more aerodynamic. There are certain equations and methods which are applied during the development process, and to keep anyone else from patenting them, I publish them (in my case, the invention is obvious from the final product). Are the competitors allowed to take the chassis I developed and use that, or do they need to design their own using my methods?