Hi Ahmad, It is not clear what you are fitting into what, so I will answer generally. Unless you are just moving things with the mouse yourself, the surface by itself is not enough to fit. You can fit atoms to other atoms, or fit atoms to a map (like a density map). If your surface is actually an isosurface of a map, then you can fit the atoms to the map. Fit atoms to atoms: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/superposition.html> Fit atoms to map: Fit in Map tool or “fitmap” command <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/fitmaps/fitmaps.ht...> <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/fitmap.html> Create a map from atoms (which could be pseudoatoms like a SAXS model): “molmap” command <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/molmap.html> Moving by hand: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/mouse.html#activedef> <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/mouse.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

On May 22, 2018, at 8:35 AM, Ahmad Abdelzaher <underoath006@gmail.com> wrote:

Hello, I have a structure that generates a surface of the biological assembly. How can I fit this surface with my structures? Regards.