Ignore PYTHON* environment variables
When I launch ovitos or use a Python script modifier, I expect to be using OVITO's sandboxed Python environment. However, I can break this, for instance if there's anything on my PYTHONPATH (someone else has previously raised this issue on the OVITO forums). I was able to get things working by setting an empty PYTHONPATH (the same solution proposed in that issue), but is there a reason this shouldn't be the default? I don't know exactly what
ovitos or the Python script modifier do under the hood, but assuming that at some point they launch Python I would expect them to run
python -E ... which automatically ignores environment variables, otherwise it breaks the expectation that OVITO's Python is completely separate from the system Python.