Hi Marie, The box is literally what data are in the map file. However, you can extend it periodically to cover molecules using the command "vop cover": <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/vop.html#cover> 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 Feb 17, 2010, at 11:39 AM, Pancera, Marie (NIH/VRC) [C] wrote:

Hi, I opened an electron density map in chimera. For some reason it is forming a box and I am not quite sure how to get the density outside of the box (to cover symmetry molecules etc...) Thanks for helping me with that. Best regards, Marie