Hi Thomas, By "selection" I will guess you mean the selected objects, not just the selection outline... In recent daily builds (Chimera 1.7) there is a "transparency" command that allows you to fade atoms, ribbons, etc. over a number of frames. For a longer time (including Chimera 1.6.x), we have had a "surftransparency" command for surfaces, but not those other items. <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/transparency.html> <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/surftransparency.html> If you are scripting this, I'd recommend just specifying the items in the command rather than making a selection and then acting on the selection.... because the selection outlines are still shown when the items are transparent. Under development are "scenes" and Animation between those scenes, which would automatically fade in/out when transitioning between scenes with different objects displayed. However, it is still experimental and not completely working. However, if you want to play around with it, see: <http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/animation/animation.html> 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 Jun 1, 2012, at 8:19 AM, Thomas Evangelidis wrote:

Dear Chimera developers, Simple question: is there any way to make a selection disappear smoothly during a movie? Thanks, Thomas