Hi Guiqing, I assume you are talking about volume data (such as a density map) since the resolution of a molecular surface would not be adjusted automatically. If so, you can just change the "step" in the Volume Viewer dialog to "1" to make sure the contour surface is based on the full data instead of a subsample. There is another setting that automatically adjusts resolution when a large data set is opened. In the Volume Viewer dialog, choose Features... Data display options. Then there should be more options shown in the dialog, including "Adjust step to show at most..." You can either change the number to something bigger, or just uncheck that option if you don't think your large datasets will be too slow to handle on your computer. If you want those settings to apply to later uses of Chimera, choose "Features... Save default dialog settings" from the Volume Viewer dialog. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. meng@cgl.ucsf.edu UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html On Feb 11, 2009, at 2:54 PM, G.-Q. Hu wrote:

Hello,

I am trying to show a large file by surface view in chimera. But I found that the structure lost the detail and the surface was smoothed. I guess there is a sampling problem for large file. Is there any way to view the large file at the original resolution?

Thanks. Guiqing