Hi Dieter, You should be able to generate a smooth volume mask using "mask ones" and "vop falloff" in Chimera. Here's an example making a smooth cylinder mask shape cylinder radius 100 height 100 caps true mask ones #0 border 10 vop falloff #1 iter 100 The boundary smoothing "vop falloff" is described on this web page http://www.cgl.ucsf.edu/chimera/data/falloff-sep2012/falloff.html Maybe you saw that page and got tripped up because it gave the wrong option name "step" instead of "iterations" in the vop falloff command -- I've fixed the web page. Tom On Nov 24, 2013, at 12:41 AM, Dieter Blaas wrote:

Hi, I was wondering whether it is possible to generate binary raised cosine smooth masks with 'masked ones' followed by 'vop falloff' or anything alike. I'd like to generate an arbitrary mask (from a volume) with a smooth transition (over some few pixels) to 0 but I did not really find adequate parameters. Is this possible? Thanks, D.

-- ------------------------------------------------------------------------ Dieter Blaas, Max F. Perutz Laboratories Medical University of Vienna, Inst. Med. Biochem., Vienna Biocenter (VBC), Dr. Bohr Gasse 9/3, A-1030 Vienna, Austria,