title: Meshlab script works from Python venv, but not after pyinstaller
body: <p>I have a simple Python script <code>Mesher.py</code> which takes file name strings in Windows format on the command line and runs MeshLab on the input point cloud (.xyz file):</p>
  <pre><code>import sys
  from pathlib import Path
  import pymeshlab as ml
  
  xyz_file = Path(sys.argv[1]).as_posix()
  output_file = Path(sys.argv[2]).as_posix()
  
  ms = ml.MeshSet()
  ms.load_new_mesh(xyz_file)
  ms.load_filter_script('filters.mlx')
  ms.apply_filter_script()
  ms.save_current_mesh(output_file)
  </code></pre>
  <p>It runs fine from the Python 3.9.6 interpreter in a virtual environment, but when I package it with pyinstaller (also installed to the venv) to make a Windows executable out of it I get this error when I run the .exe with the same command line arguments:</p>
  <pre><code>    Traceback (most recent call last):
        File &quot;Mesher.py&quot;, line 9, in &lt;module&gt;
          ms.load_new_mesh(xyz_file)
      pymeshlab.pmeshlab.PyMeshLabException: Unknown format for load: xyz
      [24580] Failed to execute script Mesher
  </code></pre>
  <p>Why does pymeshlab recognize my .xyz file fine from Python but not when the same script is wrapped up in a Windows executable?</p>
  <p><strong>EDIT</strong>
  This also happens when I use a fixed file name for my .xyz file rather than passing it on the command line, or even if I use a .ply file for the input. The .exe version of my script doesn't recognize standard MeshLab file types.</p>