Hi Elaine and Co., I am trying to color a virus map with the relevant pdb file, the series of commands I am running are as follows, open virus.mrc open virus.pdb color /A plum target c color /B lightgreen target c color /C dodger blue target c color zone #1 near #2 dist 3 However, the resultant surface is rendered in splotches of red and blue, which leads me to think the it is coloring the surface using atom type. Could you tell me how I can get Chimera X to color the surface using the colors of the chains only? FYI, color by zone works flawlessly in chimera. Cheers, Pranav -- Pranav Shah Postdoctoral Research Fellow. Hogle Lab Department of Biological Chemistry and Molecular Pharmacology, Building C2 - First Floor 240 Longwood Avenue Boston, MA 02115 (617) 432-4360 (fax) (617) 432-3839 (lab)