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How can I remove personal data from a .blend file?

I was asked to upload a .blend file in order to reproduce the issue. I removed all objects from the scene as far as possible and also removed all Python code as far as possible. This is good: it makes the file small, the sources for potential problems are eliminated and you can focus on the real problem.

However, when I look at the .blend file with Notepad or a Hex editor, it shows many paths on my system, which include my user name and other information. Note that I don't have any external references to files (like textures).


For this time, I can replace the personal data in a Hex editor, however, this is not a good approach in general, because

  • it only works as long as the file format does not use a checksum to verify the integrity of the file. (So I'm lucky it works for .blend files)
  • it only works as long as the file is not compressed, because changing a compressed file breaks the compression. (Strange enough that the .blend file is still the same even if I use compression)
  • if you accidentally delete a character (so that the file becomes smaller), the file becomes invalid
  • you need to know in advance what you're looking for (you need to know the search term) - and there might be many
  • it's a lot of work to do for something which doesn't bring additional benefit
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  • $\begingroup$ What happens if you delete the references to the paths. $\endgroup$ – Vader Apr 8 '14 at 11:39
  • $\begingroup$ @Vader: It is possible to replace it, not to delete it. I can do it that way this time, but see my updated question for the reasons I'd not like doing that in the future. $\endgroup$ – Thomas Weller Apr 8 '14 at 12:20
  • $\begingroup$ What about re-opening the file after restarting blender, and saving it out again? Not sure if this will do anything, but I'm guessing it may clear any data it doesn't need. $\endgroup$ – Greg Zaal Apr 8 '14 at 12:31
  • $\begingroup$ When you say many paths, what do you mean? I checked a file and only found 3 occurrences of my username, having saved the file on my Desktop. $\endgroup$ – iKlsR Apr 8 '14 at 13:56
  • $\begingroup$ @iKlsR: I have received the file of a colleague. The file contains paths from my PC as well as his PC. One of them refers to my Desktop, although I didn't save the file on the Desktop. In total I have 7 paths (not necessarily different) in the file which I could immediately identify as personal data. I have 10 occurrences of `C:`, which at least identifies me as a Windows user. $\endgroup$ – Thomas Weller Apr 8 '14 at 14:07
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As far as I know, there is no way to strip this information from a .blend file without editing the file itself as you have done and that has its own set of cons.

Option 1

Work at the root directory of your system. ie. C:/personal_folder/ or on a portable medium. You say you don't have any images or such attached so this shouldn't log anything private such as your username or any other personal paths provided you don't import anything and all you have is a model.

Option 2

Export to another format and reimport back into Blender. Exporting to a simple format such as .obj will only export mesh data (if all you have is a mesh) and same goes for importing it back. I did this with a file saved on my desktop and the only instance I could find with personal info was the location to the file. Use this with method 1 for optimal results.

As it addresses your other privacy concerns, being identified as to what OS you're on is fairly useless information and if you're sharing a file here, you might even be asked what os you are running so provided that no personal paths are included you should be fine.

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I edited this answer as it seemed to be incorrect.

When you find personal information in your .blend file (such as folder names), you can delete the entire DATA block that includes that information and the file is likely to still work. Do this in a copy to avoid mistakes.

Using any free hex editor (such as HxDen), open the .blend file and search for the personal information that you found in the .blend file. Personal information is usually around this string: "Save As Blender", without the quotes. Try searching for it. Now click-drag select starting from and including the "DATA" word that precedes the information that you want to delete, and select all the way until you reach the next "DATA" word. Stop the selection right before the next "DATA", don't include it in the selection. Press delete, save the file, open it in Blender and save it again so that any bad formatting is restored, if there was any.

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