Hi Murali, If I understand correctly, you want to get the area of a contour surface of the density shown using the Volume Viewer tool. If you want the total surface area, even of multiple separate blobs, use "Measure Volume and Area." If you want to measure the area of different blobs individually, use "Measure and Color Blobs." These can be started from the Tools menu of the Volume Viewer dialog, and also from the main Chimera Tools menu (Tools... Volume Data... [name of tool]). For more details on how to use a tool, press the Help button on the dialog. That opens the documentation included with your download. Our web site also has copies of the documentation: <http://www.cgl.ucsf.edu/chimera/current/docs/ContributedSoftware/measurevol/...

<http://www.cgl.ucsf.edu/chimera/current/docs/ContributedSoftware/pickblobs/p...

I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. meng@cgl.ucsf.edu UCSF Computer Graphics Lab and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html On Mar 27, 2009, at 7:42 AM, Murali Ayaluru wrote:

Dear Chimera users, I want to calculate the accessible surface area for an electron density map (mrc format) that I am working on. Can anyone, who knows how to do this, tell me how to do this? Thanks in advance for your reply, Regards, Murali