Hi Dmitry,
You could do it using "perframe" with an embedded "volume level" command in your movie script.  

For example, the following gradually changes map #2 contour level from 2.5 to 0.5 over 50 image update frames:

perframe "volume #2 level $1" range 2.5,0.5 frames 50

See the "perframe" help for details:
<https://rbvi.ucsf.edu/chimerax/docs/user/commands/perframe.html>

I hope this helps,
Elaine
-----
Elaine C. Meng, Ph.D.                       
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco


From: Dmitry Semchonok <semchonok@gmail.com>
Date: July 26, 2022 at 8:17:36 AM PDT

Thank you very much for your tips.
Works as a charm.
How 1 more question if you please -
Is it possible to record a movie while your 3D map constantly changing its threshold volume level (from low to high - which is possible to set) ?
If yes, how?
Thank you in advance.
Sincerely,
Dmitry


Although it would still be nice to have a separate option, currently
ndependent rotation can be scripted by using separate turn (or roll)
commands as in this example from Tom Goddard:

You can use the "model" and "center" options of the turn command to rotate
each model about their own center.  For example, rotating 2 models in 1
degree steps around the y axis for a total of 360 degrees

movie record
turn y 1 360 model #1 center #1
turn y 1 360 model #2 center #2
wait 360
movie encode side-by-side-spin.mp4

In this example the two models rotate at the same time.  The turn command
like other commands that create a motion returns immediately before any
motion is done to allow you to start simultaneous motions.  Then you use
the "wait 360" command to wait until 360 frames have been rendered, then
the .mp4 movie file is made.