From: John Stone (
Date: Tue Aug 18 2015 - 10:09:40 CDT

  When you load your volumetric map, what does VMD say about the
data range? When you first load your map, I would expect you to see
something like this:
  Info) Analyzing Volume...
  Info) Grid size: 169x136x138 (48 MB)
  Info) Total voxels: 3171792
  Info) Min: 0.000000 Max: 3.071364 Range: 3.071364
  Info) Computing volume gradient map for smooth shading

The "Min: xxxx" value is the part of interest if you're not seeing any
isosurface when you use a negative isovalue. What is the minimum value
in your dataset?

  John Stone

On Tue, Aug 18, 2015 at 05:31:29PM +0300, Ozan Dernek wrote:
> Hello,
> I am trying to visualize my Bader charge calculation. I stumbled upon a few web sites that say it can be done by creating two isosurfaces, and assigning same values with opposite signs to isovalue to them.
> However, I cannot get any visual from the isosurface that i assigned a negative isovalue. For example, for the first one I set the isovalue 0.06, and the second one -0.06 . As i said, the second one gives no visual.
> My question is, what does the isovalue defines here, and what can i derive from this fact that I have nothing on the negative isovalue.
> Regards,
> Ozan Dernek

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