In addition to the Python module and the command line interface, we have developed a graphical user interface (GUI) as a PyMol plugin that requires no programming skills. This GUI enables users to select a molecule and perform calculations with just a few clicks. To use it, the user simply needs to load the molecule in PyMol, open the C3 plugin, select the molecule from the drop-down list, and then press the "Calculate volume" button. Optionally, the user can adjust the grid size, select the properties to calculate (and adjust their parameters, such as the hydrophobicity method, the distance function, etc.), or choose a clustering algorithm to remove noisy cavity points, i.e. to remove isolated cavity points that do not belong to the main cavity. As an example, we provide the output obtained for the calculation of a [Pd2L4] 4+ cage providing in the same PyMol session the output obtained for the cavity, with an individual output for each selected property (Figure ).