body: I live in the US, and have been developing an add-on suite (at work) for a large CAD software suite we use (developed by, I believe, a US based company). It is, or has elements that, I feel are pretty valuable.
  
  
  What I really want to do is to re-develop it in my off time (one to make it better, my current version is rather hack-ish, and two, I know I cannot legally remove the actual data files from my company) and sell it in some form or another. Is there any specific legal reason I could not do this?
  
  
  The CAD suite this addon is for is designed with macros and addons in mind. Would this maybe be specific to the developer?
  
  
  
title: Can I legally sell a software add-on package I have developed?