Q: A tradesman (carpenter, seamstress, contractor, etc.) drafted professional plans for me. Can I take those plans to a cheaper tradesman to do the work?

A: It is clearly prohibited to ask an expensive tradesman to draft plans with the initial intention of taking them to a cheaper tradesman to make the item. You are availing yourself of a designer’s services for free, against his will and his intention to secure the job.

Moreover, even if you asked the first tradesman to draft the plans in good faith, and considered having him make the item, it is often prohibited for another tradesman to use the plans and make the item, on the basis of hasagas gevul, minhag hamedinah, dina d’malchusa, etc.

However, if the seamstress already made the dress, the carpenter made the bookcase, etc., and someone wants to show it to another tradesman to make an additional item, copying the original, it is permissible (unless the design entailed some special ingenuity). In this case the design was already sold to the customer, and the tradesman knows that he has no way of preventing others from copying it (Emek Hamishpat, Zechuyos Yotzrim, intro., 6:1-10, 22-23; ch. 36:22, 26, 28).