From: Peter Mawanga (peter.mawanga.lagos_at_gmail.com)
Date: Fri Sep 14 2018 - 04:32:10 CDT

Dear VMD users

Upon doing electrostatics calculation using "PME Electrostatics" plugin in
VMD, a ".dx" file is generated with the following output:

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# PME potential (kT/e, T=300K)
object 1 class gridpositions counts 100 100 100
origin 0.5 0.5 0.5
delta 1 0 0
delta -0 1 0
delta -0 -0 1
object 2 class gridconnections counts 100 100 100
object 3 class array type double rank 0 items 1000000 data follows
-72.1699 -71.4829 -70.5591
-69.4607 -68.2532 -66.9999
-65.7542 -64.5533 -63.4164
-62.3467 -61.3386 -60.385
-59.4842 -58.6428 -57.8751

////////////////////////////

I am not sure how these grid values are arranged as such. Although the
following link suggests that these are arranged in the format below:

https://www.ks.uiuc.edu/Research/vmd/plugins/molfile/dxplugin.html

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x1 y1 z1 value1
x1 y1 z2 value2
x1 y2 z1 value3
x1 y2 z2 value4
x2 y1 z1 value5
x2 y1 z2 value6
x2 y2 z1 value7
x2 y2 z2 value8

////////////////////////////

Please let me know if I am correct or the format is different?

-- 
Cheers
Peter