Cannot exec python postprocessor file on a MacBook

BigFarb

Hi,

I'm new here so excuse me if I wasn't able to find the existing discussion if there is any.
I need help since I'm both new to Mac and new to python. The following error gets returned whenever I slice something:
<Slic3r> Can't exec "/Users/fabian/Documents/Slic3r/postprocessor.py": No such file or directory at /Applications/Slic3r.app/Contents/MacOS/local-lib/lib/perl5/Slic3r/Print.pm line 159.
I use Repetier-Host 1.2.1, Slic3r 1.3.0, Python 3.10. on macOS Monterey.
Within Slic3r preferences and the output options I put this: /Users/fabian/Documents/Slic3r/postprocessor.py
I had to use the following executable for slic3r within Repetier-Host preferences: /Applications/Slic3r.app/Contents/MacOS/slic3r
Otherwise the integrated slic3r would return very weird gcodes, but that's another unimportant issue.
In a terminal window I added the path for the post processor:
cd /Users/fabian/Documents/Slic3r/
chmod +x postprocessor.py
The postprocessor is very crucial as it modifies the gcode to fit to a cellink bio printer which uses slightly altered codes.

I am willing to try your suggestions and appreciate help in any form.

Thanks,
Fabian

Repetier

Can you start postprocessor manually like you want? That requires first line to look like

#!python3 or python2 eventually with path

or so and x flag being set. But it needs to open it self in python to work. Otherwise you need to start python and give it the script as parameter. I guess it is something like that. Don't use python my self and the problem is within slic3r which is not our software so not so familiar with that special function.

BigFarb

How do I start the script manually?

When I double-click it it opens in Idle and the script is displayed with some commands being colored.

BigFarb

The first line reads:

#!/usr/bin/python

Repetier

If you can start it in your terminal then it should probably work (assuming the command replacement works there as well).
Does /usr/bin/python exist and lead to correct python version? With latest release Apple removed python 2 in Monterey and python 3 is not backward compatible 100%. If you need a special version replace path with correct path for required version.

BigFarb

Ok, I got there by using the terminal, typing cd usr/bin/python and then double clicking the terminal window headline.
(I don't know how one would access this path normally ... anyway)
I found the "python3" file there but not such thing as just "python". When I double-click it, the system asks for the "command line developer tools" to be installed, should I?
<blockquote class="Quote">

Repetier said:

If you need a special version replace path with correct path for required version.

Could you please detail this step for me a little? I'm guessing I would have to download/install another python version and replace the first line in my post-processor script?

Repetier

cd changes directory and python is executeable so "cd usr/bin/python" makes no sense apart from bing reletive. Try
ls -l /usr/bin/python
to see your installed python executeables in /usr/bin. Check also
ls -l /usr/local/bin/python

I have so many python versions on my pc I can't say which is originally from apple if any. As said python 2 is not included any more in Monterey, but was in older versions.
If you do not have a proper python version check google. As said I'm not using actively python as I do not know that language from programming. Just from some scripts using it.

Anyhow try just typing
python
and at the end press tab 2 times to see possible commands starting with that. Then check that file + script as parameter and gcode file as second parameter if it works with your python script. It is not from us so can not say anything about it.

BigFarb

Good morning,
I tried the things you suggested and what worked in the end is the following:

(Disclaimer: I checked with "s -l /usr/bin/python" and "ls -l /usr/local/bin/python" and I only have python3)
-Putting the "3" at the end of the starting command of the script so it goes "#!/usr/bin/python3"
-Downloading and installing the developer tools for the command line (though the Mac did this automatically after asking .. so I don't actually know what was actually installed and I also don't know how to uninstall it therefore)

Nevertheless everything is working now as it's supposed to! Thank you so much for your support :)