Hi JD, You can split the surfnet surface into separate selectable pieces by selecting the whole surface (ctrl-left-button) then using keyboard shortcut "Sc" (split connected pieces). You have to enable keyboard shortcuts with menu entry Tools / General Controls / Accelerators On. After this you can select individual pieces and measure their volumes with the "mv" shortcut. You can select all of the pieces and use "mv" to get a list of volumes for all the pieces. "ma" lists areas. Each piece is numbered and you that number will be shown in a pop-up if you the mouse over it. You can run the measure volumes shortcut (mv) from Python code using: import MeasureVolume MeasureVolume.report_selected_volumes() This code is in your Chimera distribution in chimera/share/MeasureVolume/__init__.py. Tom