"Christopher James Huff" <chr### [at] maccom> wrote in message
news:chr### [at] netplexaussieorg...
> In article <3c4234ef@news.povray.org>,
>  "Mitchell Waite" <mit### [at] dnaicom> wrote:
>
> > Can anyone point me to an example that shows how to make my spotlight
appear
> > to have a cone of light seem to emanate and also glows without haven't
to
> > use atmosphere (which seems to slow my rendering way down and adds too
much
> > stuff outside my light area)?
>
> Well, first, "atmosphere" is an obsolete feature, it has been replaced
> by "media" in POV 3.1. POV 3.5 is currently in beta, you really should
> upgrade to at least POV 3.1.
> Anyway, the reason it is slow is the extra calculations for doing the
> light scattering...you pretty much have to choose between fast rendering
> and no light beams or slow rendering with visible beams. However, the
> MegaPOV unofficial patch and the POV-Ray 3.5 beta have additional
> sampling methods that can let you get away with much faster settings, so
> you may want to check them out.
>
> Or you might be able to fake it using a semitransparent cone or a
> transparent cone filled with emitting media (which will render faster
> than scattering media).

Here's an example of that, which would need adjusting for individual scenes:


camera {
  location  <0, 1, -5>
  right     4/3*x
  look_at   0
}

#declare S=3; // scale or width of beam
#declare D=10; // distance needed

#declare ConeOfLite=
cone {
        0,0,y,1
        pigment {rgbt 1}
        interior {
                media {
                        emission 0.67/S // intensity of air glow
                        density {
                                cylindrical
                                }
                }
        }
 scale <S,D,S> // x and z are width, y is length or distance
 hollow
}

light_source {
  0, 1
  spotlight
  point_at y
  radius 4*S
  falloff 8*S
  looks_like {ConeOfLite}
 rotate <120,90,0> // turn to point somewhere
 translate <-3,2,0> // lights position
}

plane {y,-1
        pigment {rgb <.9,.6,.3>}
}


bob h

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