topic Re: Can PythonStartup path be set with .mod modules? in MotionBuilder Forum

Can PythonStartup path be set with .mod modules?

FirespriteNate — Fri, 07 Nov 2025 10:34:01 GMT

We need to set a custom PythonStartup path that is on our project work drives under P4 control. At the moment I am setting it (along with other stuff) using a launch script, something like this:

motionbuilder.exe -verbosePython d:\mobu\start.py

and in start.py is something like:

from pyfbsdk import * config = FBConfigFile("@Application.txt") config.Set("Python", "PythonStartup", "d:\\mobu\\start_dir", "Set by start.py")

This is grossly oversimplified for clarity, but is there any way to ditch all this and just set this custom PythonStartup path from within a .mod file?

Re: Can PythonStartup path be set with .mod modules?

Ndgt — Sat, 08 Nov 2025 08:00:10 GMT

Hi, @FirespriteNate

Though module description files (.mod) will not modify PythonStartup, it is possible to specify some custom path for MotionBuilder to look into at startup.

For example, put this .mod file in the directory as the Developer Help describes.

+ CustomPythonStartup 0.1 C:/Mobu_Python/Forum/CustomPythonStartup python: startup_scripts python_sys_path: path_for_syspath

This is the result output of startup.

Of course, we can specify the module path as startup path directly.

+ CustomPythonStartup 0.1 C:/Mobu_Python/Forum/CustomPythonStartup python: .

With this .mod file, the scripts under the CustomPythonStartup will be executed at startup.

Hope this helps.

Best Regards,

Ndgt

Re: Can PythonStartup path be set with .mod modules?

FirespriteNate — Mon, 10 Nov 2025 11:47:31 GMT

Many thanks, that seems to work!

I started setting this up on MoBu 2022 which has no modules, hence the rather convoluted PythonStartup approach, but this is much better.

I knew I could add paths to a module, but I didn't realise adding a path to "python" would auto-run the files within it!