I need to debug an add-on in real-time (installed & running in Blender).

While I am an experienced programmer in several languages, Python is not one of them.

I'm trying to fix an add-on written by someone else. Released as a Beta, the creator is no longer around to finish the job.

The add-on is active from the moment Blender starts (adding a new tab to the left margin), so placing "debugger" commands at the top of the script only crashes Blender.

Unfortunately, I can't post the code for the following reasons:

  1. It's not mine.
  2. It's too big.
  3. It calls in-house apps to work, so you couldn't run it anyway.

I know what the problem is (it's writing to the wrong path) but not why. If only I could set breakpoints and view the contents of variables at various times, I'd be set.

Any advice is appreciated.


1 Answer 1


Run blender straight from the command line...then watch the console for the errors. If blender quits, the info will be printed out. Also, add printouts or setup a python logger to "view the contents of variables."

I can't really think of any other ways to help other than these suggestions without seeing the code (or even a description of what happens when the "bug" occurs).

  • $\begingroup$ Thanks. I'll try that. I'm a bit of a Blender newbie as well as a Python novice, so I guess I have some learning to do. :/ Unfortunely, the script isn't throwing out any errors. As far as it is aware, it is writing out everything exactly where it's supposed to. :D $\endgroup$
    – Mugsy
    Sep 9, 2016 at 19:58

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