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Hi,
Scene: one spotlight, one coloured glass ball (photon target on for
reflection and refraction, collect off), white plane below ball; setting up
photons only using spacing and autostop. Povray 3.6.1 for windows.
Without photons enabled: a coloured shadow from the glass ball
With photons: some caustics, but the coloured shadow has become grey.
Is this normal behaviour? Why would the colour disappear?
bye,
gert
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"gvdeynde" <gvd### [at] hotmail com> wrote in message
news:433c3135$1@news.povray.org...
> Hi,
>
> Scene: one spotlight, one coloured glass ball (photon target on for
> reflection and refraction, collect off), white plane below ball; setting up
> photons only using spacing and autostop. Povray 3.6.1 for windows.
>
> Without photons enabled: a coloured shadow from the glass ball
> With photons: some caustics, but the coloured shadow has become grey.
>
> Is this normal behaviour? Why would the colour disappear?
this is normal behaviour, and it's the realistic thing to happen, although you
might expect otherwise. But just try it: fill a glass with a coloured but
transparent fluid, for example ice-tea, and shine a light through it. Now look
at the shadow of the glass, you will notice that it's mostly just dark,
uncoloured shadow and only the caustics have some of the colour of the fluid.
After that, you can enjoy a nice glass of ice tea to celebrate the newly learned
facts about light and shadow! :p
cu!
--
#macro G(b,e)b+(e-b)*C/50#end#macro _(b,e,k,l)#local C=0;#while(C<50)
sphere{G(b,e)+3*z.1pigment{rgb G(k,l)}finish{ambient 1}}#local C=C+1;
#end#end _(y-x,y,x,x+y)_(y,-x-y,x+y,y)_(-x-y,-y,y,y+z)_(-y,y,y+z,x+y)
_(0x+y.5+y/2x)_(0x-y.5+y/2x) // ZK http://www.povplace.com
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> > Without photons enabled: a coloured shadow from the glass ball
> > With photons: some caustics, but the coloured shadow has become grey.
The shadow itself should be dark grey, because no light (and thus no colored
light) is reaching that area. However, the *caustics* (the disturbed lit
areas) should still be colored, if you're using a filtering pigment.
- Slime
[ http://www.slimeland.com/ ]
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"gvdeynde" <gvd### [at] hotmailcom> wrote:
> Hi,
>
> Scene: one spotlight, one coloured glass ball (photon target on for
> reflection and refraction, collect off), white plane below ball; setting up
> photons only using spacing and autostop. Povray 3.6.1 for windows.
>
> Without photons enabled: a coloured shadow from the glass ball
> With photons: some caustics, but the coloured shadow has become grey.
>
> Is this normal behaviour? Why would the colour disappear?
>
> bye,
> gert
You didn't mention if you were using an interior with ior (index of
refraction) with the ball. If you are, try adding some dispersion. You'll
get colors!
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