Hi, There isn’t an option to draw the symmetry axes in this tool. However, the orientation options in the Icosahedron Surface tool describe which direction it is, for example "x 2-fold, z 3-fold (2n3) - with a two-fold symmetry axis of the icosahedron along the x axis and a three-fold symmetry axis along the z axis” <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/icosahedron/icosahedron.html> So if you pick the orientation named “2n3", the 3-fold axis is pointing straight at you going in and out of the screen. You could try creating the axis as a 3D object by making a BILD format file. For example, if you made a 2n3 icosahedron with radius 100, you could create a text file named something.bild containing something like the following lines and open it in Chimera: .color yellow .cylinder 0 0 -100 0 0 +100 5 See BILD format description: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/bild.html> I also attached this as a file named test.bild (just open with “open” command or menu: File…Open). You can change the color, coordinates (length and direction), and the radius, and also there are other BILD shapes available, such as arrow instead of cylinder. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

On Sep 17, 2019, at 7:24 AM, sunyeping <sunyeping@aliyun.com> wrote:

Dear everyone,

I created an icoshedron with "Tool>high-order structre>Icoshedron surface" menu. Do you know how to draw 3-fold axis of a Icosahedron so that I can see the 3-fold symmetry center on the icoshedron surface? Thank you in advacne. _______________________________________________ Chimera-users mailing list: Chimera-users@cgl.ucsf.edu Manage subscription: http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users