title: How to determine if DWG was made in foreign program
body: <p>I'm currently developing a solution that utilizes Open Design Alliance to read DWG files. I'm trying to implement a similar feature that exists in the AutoCad program itself -- AutoCad will notify the user if the file's origin is not from a licensed AutoCad application. (<a href="https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/sfdcarticles/sfdcarticles/Open-foreign-DWG-file-message-appears-in-AutoCAD.html" rel="nofollow noreferrer">See Here</a>)</p>
  
  <p>I have explored the library in depth and have concluded that the information I need to determine this is most likely available but I'm having a hard time figuring out what the guidelines are that signify the file is from AutoCad origin, or not. Any Ideas?</p>