How did pymol select the dots of the .opendx file?

[NoMatter-98]

I use apbs and get opendx file, then load it into pymol and show the dots It shows like this:

but how can i select the very part i need? ### Here I need to find the coordination of the white dot. How did you show the opendx file? opendx file contains large mounts of chargeValues, in this case ,the mesh size is 129129161, the opendx file contains every dots' charge value, but when it was loaded into pymol only the protain like part dots were reserved. I changed half(x from 0 to 60 and all the y , z) of the charge value into a specific value and it shows like this:

But i set the chargevalue into 0 ,1,-1, the picture is the same.

I saw the same problem issued by other people in other platform but they seems gave up. It would be very helpful if you could help us solve this question. Thanks a lot!