Besides the secondary structure type (ss_type) you may also need to think about the secondary structure element identifier (i.e. are you sure it's at the end of the strand and that all the residues in the strand are in the same strand?) which is attribute ss_id <https://rbvi.ucsf.edu/chimerax/docs/user/attributes.html#residue> ... these have been discussed on the list several times, but not in regards to strand arrowheads specifically. <https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/...> <https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/...> That's my only substantive idea. If both of those attributes are the way you want, then try hiding and re-showing the ribbon, or finally, using Help... Report a Bug and attaching everything needed to reproduce the problem (e.g. a session) and include an explanation of what exactly is wrong, and your email address for feedback. 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 Apr 12, 2025, at 8:53 AM, Lee Bardwell via ChimeraX-users <chimerax-users@cgl.ucsf.edu> wrote:

Hi Elaine and team,

I’ve noticed an issue that sometimes happens when I change some residues to a beta strand, e.g. setattr /A:149-151 res ss_type 1. Sometimes an arrowhead is not placed at the end of the strand. Am I doing something wrong? Or is there a way to force an arrowhead?

Thank you! _________________________________

Lee Bardwell, Ph.D. Professor and Vice-Chair, Dept. of Developmental & Cell Biology Charlie Dunlop School of Biological Sciences University of California, Irvine __________________________________