Thanks for the advice. You were right in that the background designator was
not the only thing defining the "background". The fog designator was the
problem, as it apparently put a black fog behind my molecule. Once I
removed it, I got a nice transparent background (original header below).
#include "colors.inc"
camera {
orthographic location <0,0,-60>
look_at <0,0,0>up <0,35.2678904747,0>right <36.5470367614,0,0>}
background { color rgb <0,0,0> }
light_source { <0.0,0.0,-600.0>color White}
fog { distance 100 colour rgb<0,0,0> }
Thanks,
Ray
On 6/1/07, James Stroud <[log in to unmask]> wrote:
>
> 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 ([log in to unmask]).
>
> 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
>
--
Raymond W. Bourdeau
University of Chicago - Tang Lab
929 E 57th St. W423J
Chicago, IL 60637
tel: 773-702-4608
email: [log in to unmask]
email: [log in to unmask]
