Dear Bhaskar, As explained in more detail here: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/representation.html#surfaces> ...when you show a molecular surface in Chimera (e.g. menu: Actions... Surface... show) it will automatically calculate solvent-accessible surface (SAS) and solvent-excluded surface (SES) areas. The total is reported in the Reply Log (in Favorites menu), but also per each atom and each residue. The per-atom and per-residue area values are attributes named areaSAS and areaSES. In the Render/Select by Attribute tool (menu "Select... By Attribute Value" or "Tools... Depiction... Render by Attribute"), you can: see a histogram of the values, select or color atoms by the values, or (using its File menu) write a text file with the values. <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/render/render.html> <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/render/render.html#saving> Or, to report per-atom values in the Reply Log instead of writing a file, you could use the "list atoms" command, for example: list atoms attribute areaSAS <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/listen.html#listatoms> More about attributes here: <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/defineattrib/defineattrib.html#attribdef> There is also an attributes tutorial: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/tutorials/attributes.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco On Apr 4, 2014, at 8:33 AM, Bhaskar Bagchi wrote:

Respected Sir I want to calculate surface area of different atoms in a molecule. Is it possible in chimera? Please help me.