Question about Atom Volumes and Surfaces Tool

Dear all,
I have already known that I can calculate the occupied and free volume of my system by the tools of atoms volumes and surface. This tool can also show the surface of my system, as shown in the figure below:
User-added image
But for each point in my system (XYZ positions are known), how can I do this point lies in the occupied volume or free volume? Thanks.
Best regards,
Yours
CHENG Xu