Hi Yaikhomba, I believe you need to get a newer version of ChimeraX, probably the daily build. I don't remember exactly when the "angle" command was added, but the help page link you sent shows modification date Sept 2020 at the bottom: <http://www.cgl.ucsf.edu/chimerax/docs/user/commands/angle.html> ChimeraX 1.0 is from June 2020. If you don't seem to have a command but you can see documentation for it, in general, first try getting a newer version of the program. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

On Nov 27, 2020, at 7:23 AM, Y. Mutum <ym337@cam.ac.uk> wrote:

Hi I am trying to measure angles between three atoms using ChimeraX by typing

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angle #1/a:1001@FE, #1/d:1001@FE,#1/a:141@C

However, the log reports: angle #1/a:1001@FE, #1/d:1001@FE,#1/a:141@C Unknown command: angle #1/a:1001@FE, #1/d:1001@FE,#1/a:141@C

I have also tried to check if 'angle' is a valid command in the ChimeraX window I have opened.

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usage angle In Log ---> "angle" is not a command name

However, angle does seem to be a valid command in ChimeraX. In the documentation here -- http://www.cgl.ucsf.edu/chimerax/docs/user/commands/angle.html.

I am using ChimeraX-1.0 ( version: 1.0 (2020-06-04))

I might have missed things out - Could you please give an idea of how i could measure angles using the command line in ChimeraX?

Thanks Yaikhomba