COSMO Surface Viewer Build colored surface charge or potential surfaces from ORCA's .cpcm files and view or render them. Features Parses .cpcm to points, potentials, areas, and sphere owners Builds faces with neighbor filtering and ownership constraints Maps potentials to colors using a configurable Matplotlib colormap Writes VRML (.wrl) and renders to .png with off‑screen or on‑screen modes

Surface charges of succinic acid in water

Quick Start

• Python 3.9+

• Create a virtual environment and install requirements:

  • python -m venv .venv && source .venv/bin/activate
  • pip install -r requirements.txt

• Place your .cpcm files in ./input/ (or point to a different folder).

• Generate .wrl and .png with defaults:

  • python cosmo_render.py

CLI Usage

• Show all options: python cosmo_render.py --help

Common flags

• --input: input directory with .cpcm files (default: input)
• --output: directory for .wrl and .png files (default: output)
• --force: rebuild and re‑render even if outputs exist
• --onscreen: use on‑screen rendering (off‑screen by default)
• -v / -vv: increase verbosity

Examples

• Small halides in water: You can see the change in the sigma hole in those images.

CH3Br in water.

CH3I in water.

• Aspartic acid surface charges during SCF iterations:

Using VRML with other software

• The generated .wrl files can be opened in, e.g., UCSF Chimera for interactive viewing alongside molecular structures (e.g., an .xyz or PDB file). Chimera project: https://www.cgl.ucsf.edu/chimera/

Packaging (optional)

• A minimal pyproject.toml is included. Install editable and use the console script:

  • pip install -e .
  • Run: cosmo-render --help

Notes

• Off‑screen rendering requires a working VTK/PyVista setup; depending on your platform you may need system OpenGL or OSMesa. If off‑screen fails, try --onscreen.
• Output directories are created automatically.