Hi Vincent, Maybe you are referring to "silhouette edges" - these are absolutely controllable, however, either by choosing a Preset that does or does not include them (from the Presets menu) or by opening the Effects tool (under Tools... Viewing Controls) and turning them on or off. http://www.cgl.ucsf.edu/home/meng/docs/UsersGuide/menu.html#menupresets http://www.cgl.ucsf.edu/home/meng/docs/UsersGuide/sideview.html#effects That seems the most likely to me. Otherwise, I have no idea why black edges might appear in the interactive Chimera display (graphics driver bug?). 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 Dec 14, 2007, at 9:59 AM, Vincent Racaniello wrote:

When I display a protein as an edged ribbon, sometimes they have a black line on the edges, other times none. There seems to be no consistency in this behavior. The same also happens with surfaces. Is there a way to regulate this appearance?