If permission is sort to use design elements and credit given to the original designer for the idea and/or royalties as appropriate, then I wouldn't have a problem with it. Its when this is not carried out that I find it in very poor taste.
Another example of a similar circumstance to this is the use of data's
databank 70 as the basis for the structural design of a light called
xm-18 by one of the leading manufacturers on this forum. As far as I know, no credit was ever given to data or the databank 70 for this either.
Honestly, although there are some structurally similar designs between the db70 and the xm18, it seems to be (in final form and function) quite a different beast. Active cooling, dedicated power source, modular...Even IF the xm was based loosely off of the DB, in the end, it is a very different light.
From an engineering standpoint, hexagons are among the most structurally sound modular shapes around. The case between the spy007 and the zip20 is much more controversial, because niteeye blatantly and adamantly claims that this 'was their design' and that 'any resemblance'( including and implying structural design, layout of user interface, power source, and overall dimensions) was purely coincidental, and that CPF was part of a 'slanderous accusation' that was orchestrated as part of Nitecore's devious schemes to 'bring down' the respectability of jetbeam/niteeye. I think that just adds fuel to our fire.
If I read that statement wrong from Niteeye, somebody please correct me. I know firsthand that many OVERSEAS based companies and manufacturers will talk in such a way to play the victim and to deny as many allegations as possible. They will even go as far as to lie and make claims that they know cannot be validated, such as their claim of pure developmental coincidence. They do NOT care, as long as they make a quick buck.