I'm attempting to run a python script that creates a custom menu inside Maya when a .bat file is opened to start Maya. The python script is not inside the Maya project and I wanted to add the path in the batch file. I have this in the .bat file:
start D:\TOOLS\Maya2019\bin\maya.exe -command evalDeferred(python('execfile(\"D:\CustomMenu_startup.py\")'))
Several attempts already but it's returning a syntax error.
solved by using:
start D:\TOOLS\Maya2019\bin\maya.exe -command evalDeferred(python(\"execfile('D:\\CustomMenu_startup.py')\"))
I'd suggest that, as a rule, it'd be better to push the deferred evaluation into the python itself. That way you don't have to think about it in all 3 languages (BAT, MEL, and Python).
There may also be parts of the work you can execute before the main Maya event loop kicks in, which will save some startup time -- evaldeferred is the safe choice before touching the Maya UI or the scene but you might have other jobs (like downloading files or checking the user's disk) that can be done safely while Maya itself is still loading. That's another reason to do the deferred part in Python instead of in the outermost MEL call.
If you're interested in generating launchers like this you can simply distribute a mel file instead of the BAT; MEL is executable by Maya as a file argument so your commandline gets simpler and if you have the correct file associations set up it's double-clickable.
You might also want to check out these blog posts about how to create python launchers for Maya: https://theodox.github.io/2018/pythonception#pythonception https://theodox.github.io/2018/keystone#keystone
