For povray, background is implicit (it exists as black if unspecified). According to the docs "when the alpha channel is turned on, all areas of the image where the background is partly or fully visible will be partly or fully transparent". I haven't used ccp4mg, but it might be making a sphere or a sky_sphere for the background instead of using the "background" designator, which could be causing problems. I suspect this is the case. Spheres are not transparent unless specified with an rgbt color_vector in the pigment specifier. Setting 1.0 as the 4th term in the rgbt vector will give full transparency. Also, some viewing programs do not display the alpha channel and they will look non-transparent, but this is less likely than the sphere or sky_sphere scenarios.
If you post your pov files somewhere, I can give them a look. You will probably not want to attach them if you post to the ccp4bb as they can be quite big, but you can include them as attachments if you mail them directly to me ([EMAIL PROTECTED]). James On Friday 01 June 2007 10:54, Ray Bourdeau wrote: > Hi all, > > I am generating images using ccp4mg (which is wonderful by the way), but I > can not figure out how to generate a povray input file that will yield an > image with a transparent background. Getting a transparent background > using the screen snapshot works fine, but I would like to have a rendered > image. I have tried adding the +UA tag (which I believe should render the > alpha channel as transparent) as a povray command line option so that my > input looks like such: > > povray +A +J0 +Q9 +UA +H2400 +W2400 input_file.pov > > Yet this still does not give me a transparent background. When generating > povray input files, does ccp4mg output the background as the alpha channel > or do I need to go about this a different way? > > Thanks, > > Ray -- James Stroud UCLA-DOE Institute for Genomics and Proteomics Box 951570 Los Angeles, CA 90095 http://www.jamesstroud.com
