Hi Dario,
This is explained in the palette documentation -- see the third method with value,color pairs:

<https://rbvi.ucsf.edu/chimerax/docs/user/commands/color.html#palette-options>

In your case, something like:

color byattribute seq_rmsd  #1 palette 0,blue:3,white:6,red

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

> On Apr 19, 2022, at 9:05 PM, Dario Passos via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:
>
> Dear Chimera community,
> does anyone know how to add a range of values for the rmsd colors in Chimera X? Something like this (below) in angstrom:
>
> => color byattribute seq_rmsd  #1 palette blue:white:red threshold 0:3;6
>
> Thanks,
> Dario