body: There is a video game called Minecraft, in which you can build structures (e. g. houses). Some people publish them on publicly accessible sites such as PlanetMinecraft.com as sets of files in format A.
  
  
  Imagine, I do the following. I take such collection of files in format A and transform it (manually, automatically or semi-automatially) into format B. I have my own, custom software, which takes format B files as input and then recreates these structures in user's Minecraft in format A (they are not exactly the same, but similar). I intend to give access to that software for a monthly fee.
  
  
  Format B is my own format and its files are smaller and easier to share and modify than format A.
  
  
  Am I allowed to 
  
  
  * create format B versions of structures on PlanetMinecraft and
  * distribute them for free
  
  
  in the following 2 cases under American law?
  
  
  **Case 1:** The author of the structure allows to download and distribute the format A file, but does not allow to modify it (according to the copyright statement on the structure page). Technically, I'm not modifying format A file, I read it and create format B file based on information in the format A file.
  
  
  **Case 2:** I write to the author of the structure (ask him or her whether or not I'm allowed to do this with his creations), but don't get a response within 1-2 weeks. There is no clear information about the type of license his work is published under.
  
  
  **Analogy:** You see someone's house and walk around it several times. That house is format A file. Then you sketch a plan of that house (format B file), which you distribute for free.
  
  
  
title: Is it legal to reverse-engineer structures on PlanetMinecraft?