Hi Nihshanka, If you want to just dump all the xyz coordinates of the surfaces points and the electrostatic potential you could modify the Chimera code in a small way. You would modify file chimera/share/Surface_Color/__init__.py using any text editor. After line 157 def point_colors(self, vertices, vertex_xform): values, outside = self.volume_values(vertices, vertex_xform) add the "for" and "print" statements shown below. def point_colors(self, vertices, vertex_xform): values, outside = self.volume_values(vertices, vertex_xform) for i in range(len(values)): print vertices[i], values[i] Indentation is important so indent as shown. This change will print each xyz coordinate and the potential value to the Chimera reply log (menu Favorites / Reply Log). Printing a huge list of surface points and potential values may not be that useful since it will be hard to determine what atoms the surface points are near. Here is a differnt approach to check the potential at specific points. The basic idea is to place a marker and move it to where you want to know the potential. Place the marker using volume path tracer, menu entry Tools / Volume Data / Volume Path Tracer. Turn on the switches "Drop markers on empty space" and also "Move markers with mouse" in the path tracer dialog. Then click with mouse button 3 with the Ctrl keyboard key held down to drop a marker. You can drag the marker using Ctrl-button-3 to whatever location you want. Now use the Values at Atom Positions tool, menu entry Tools / Volume Data / Values at Atom Positions. Select "marker set 1" from the Molecule menu. This is the fake molecule that contains the marker you just dropped which is a fake atom. Now press the Histogram button on the values at atom positions dialog. That will show another dialog giving the potential value at the marker position. To get the value at a new position, drag the marker and press the Histogram button again. Would be nicer to be able to just click on the surface to get the potential value at that surface point. That is not currently possible but I'll add to my list of requested features. Tom