Suppose I purchased a close-up trick with a clever mechanism, and wanted to build it into a larger piece. To actually build the prop as a larger illusion, possibly with a new exterior, but with the same mechanism.

What if I purchased a large illusion, and then built a small version for close-up?

Assuming you are just performing them and not selling them, and that you have purchased the original product or design, where are the boundaries on these types of alterations or re-designs? In general the legality is pretty simple to determine in each case, but I'm interested in how creators feel about these things, and whether there are standards in the community.

I have a specific idea that I'd be willing to share over PM with someone knowledgeable, but my creative tendencies are in this direction so I'd love some general input as well.

I personally see no issue with it, especially if you are not doing so to resell the props but for your own use. I've done the exact same thing a few times with some of my props. Or, I have built a similar prop with modifications or a different design of one I owned.

I also have changed sizes of props that I have bought....Go for it!

I did the same thing with Dean's Box, I wanted to make it Palm Size. I simply called up Dean, asked his permission and he said sure.. Check with the creator, most likely they won't mind.

Jake Jr.