Multiwfn forum

smile

Member

Registered: 2025-04-15

Posts: 1

Trouble Following MEP+VDW Surface Visualization in VMD

Hi,
I'm trying to follow this tutorial to visualize MEP on a van der Waals surface using VMD and Multiwfn:
? https://www.youtube.com/watch?v=QFpDf_GimA0 But I got invalid command errors in VMD like iso, pt, and esp.
So I tried the second method, loading the files manually in VMD:

I exported surfanalysis.pdb, geometry.pdb, and mapfunc.cub from Multiwfn (from options 2, 5, 13).
I load them in VMD manually, but I have problems:
I can set isovalue to 0.001 or 0.002 in VMD

But the color scale range (e.g., -0.002 to 0.002) resets to 0 unless I use larger values like 0.01

The isosurface appears:

In one color only

Or with overlapping red/blue

Or broken with holes unless isovalue is ≥ 0.01

I tried different grid spacings in Multiwfn (0.2, 0.15, 0.1) — no success. Also tested VMD versions 1.9.1, 1.9.3, and 1.9.4.
Help Needed:
How to fix the color scale reset issue?

How to get a closed transparent red–blue surface at isovalue 0.001?

Is there a custom VMD version with iso, pt, esp commands like in the video?

Any working .tcl script or .vmd template for this setup?

Thanks in advance!

Last edited by smile (2025-04-15 14:53:27)

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,965

Website

Re: Trouble Following MEP+VDW Surface Visualization in VMD

Don't worry, you can input e.g. 0.002 in the text box of color scale of VMD and press ENTER button, it will take effect. Although then you will see 0.00, it doesn't matter, because the text box only show two decimal places.

Alternatively, you can use ESPiso_eV.bat along with ESPiso_eV.txt in "examples\drawESP\" instead of ESPiso.bat along with ESPiso.txt. In this case, the grid data of ESP exported by Multiwfn will be in eV, so you can input the color scale in VMD in a much larger magnitude.

Alternatively, you can use VMD command to directly set the color scale. In ESPiso.vmd you can find the following two lines, you can change the values and run them in VMD console window manually.

set colorlow -0.03
set colorhigh 0.03