[Chimera-users] Chimera command to set the volume contour surface threshold

Hi, I am new using Chimera and am writing a script to generate automatically some volume contour surfaces. I would like to know if there is command to set from the script the volume contour surface threshold? I came across a post from 2006 (https://www.cgl.ucsf.edu/pipermail/chimera-users/2006-November/001121.html) where it was mentioned that such command did not exist by that time. I hope there is one now! Thanks a lot, Irene