Hi Prashant, Maybe the basic problem is that you are not using ball-and-stick style? If you are using spheres it is just showing the VDW radii and does not use ball scale. If you are using sticks only, they do not use the atomic radii at all. You have to choose the style that is actually ball-and-stick. Then, command to use is "size" -- looks like your size commands may be correct. As it says in the help <https://rbvi.ucsf.edu/chimerax/docs/user/commands/size.html> ... the ballScale is multiplied by the VDW radius of the atom, and the initial default is 0.3, but you have to be using the ball-and-stick style to see any difference. So this works fine for me: open pubchem:14141 style ball size #1 ballScale 0.4 As described in the "size" help, you could alternatively change the VDW radii instead of the ball scale, although that would also affect any calculations that use VDW radius (molecular surface, surface area, contacts, etc.) The size command is also used to change stick thickness (initial default 0.2) in either ball-and-stick style or sticks-only style. size stickRadius 0.4 To see the "size" help you can just use command "help size" or you can view the copy at our website linked above. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco

On Jul 7, 2025, at 8:50 PM, Singh, Prashant Kumar via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:

Hi,

I have recently downloaded Chimera x 1.10, in which I am trying to change the size of sticks and spheres in ball and stick model but the commands I am trying to were not working with error message "Expected a keyword" Here are the commands which I am using Style stick/sphere set stick/sphereRadius 0.3 setattr Radius 0.3 target #3 set stickRadius 0.3 target all size #1 ballScale 1.5 size #1 ballScale 1.5 size #1 ballScale 1.5 setattr m ballScale 0.5 style ligand ball vdw scale 0.8 set stickRadius #3 0.35 set stickRadius 0.3 target sel set stickRadius 0.3 target all set stickRadius 0.3 target all set stickRadius 0.3 target all

Unfortunately none of them is working in my command line, will you guys plz help me to to change the size of sticks and sphere in ball & stick model. i am using iMac computer.

Best regards Prashant