Hi there!

I've gotten stuck in an image I'm working on and would like
some information regarding photon lightmapping:

Are the photons brightness dependant on the lightsources RGB
they are shot from? Or are the RGB-values normalized?

Is there a way to use colored photons without showing the
lightsource (and its normal effects of colored lighting)?

If you have a look at the "WIP Sculpt ..." in povray.binaries.images,
you'll see where I'm actually targeting my questions on, and might
know some solution to what I trying to do...

Thanks in advance!

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html

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In article <3C4F089A.6D586854@gmx.de>, Tim Nikias <tim### [at] gmxde> 
wrote:

> Are the photons brightness dependant on the lightsources RGB
> they are shot from? Or are the RGB-values normalized?

They are dependant on the brightness of the light. Double the brightness 
and your caustics get brighter, any other way wouldn't make sense.


> Is there a way to use colored photons without showing the
> lightsource (and its normal effects of colored lighting)?

You mean you want caustics to be colored, but direct lighting to be 
white? Why?
It could probably be done with light groups, but I haven't done anything 
with that particular feature...maybe a colored light which shoots 
photons at an invisible "ghost object", but doesn't interact with 
anything else, and a white light which interacts with the scene, 
including a "real" version of the object.
The light source itself will only be visible if you use looks_like or 
scattering media.


> If you have a look at the "WIP Sculpt ..." in povray.binaries.images,
> you'll see where I'm actually targeting my questions on, and might
> know some solution to what I trying to do...

I'm not really certain what you're asking...it looks like you 
accomplished what you wanted.

-- 
 -- 
Christopher James Huff <chr### [at] maccom>

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> You mean you want caustics to be colored, but direct lighting to be
> white? Why?
>

In the mentioned image "WIP-Sculpt", the reflection of photons cause them
to gradually change their color (into something more greenish, because
the surface-pigment is rgb <1,.5,0>, and at some point, I get lots of
red and some green photons). I wanted to have only orange photons,
not ones with changing colors (looks somewhat strange, even if
calculation-wise correct). But the scene itself should be lit with white...

> It could probably be done with light groups, but I haven't done anything
> with that particular feature...maybe a colored light which shoots
> photons at an invisible "ghost object", but doesn't interact with
> anything else, and a white light which interacts with the scene,
> including a "real" version of the object.
>

I could try that, good idea, though I think I'll leave my Sculpt finished
now...

> The light source itself will only be visible if you use looks_like or
> scattering media.
>

Yup.

> I'm not really certain what you're asking...it looks like you
> accomplished what you wanted.
>

I already mentioned what I wanted above, so I won't duplicate
my sentences (#if (Words=Said) #avoid Spam #end).

Thanks for the answers, it helped (or will, to be honest).

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html

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In article <3C51621B.2B9642DE@gmx.de>, Tim Nikias <tim### [at] gmxde> 
wrote:

> In the mentioned image "WIP-Sculpt", the reflection of photons cause them
> to gradually change their color (into something more greenish, because
> the surface-pigment is rgb <1,.5,0>, and at some point, I get lots of
> red and some green photons). I wanted to have only orange photons,
> not ones with changing colors (looks somewhat strange, even if
> calculation-wise correct). But the scene itself should be lit with white...

Are you using metallic reflection? If not, try turning it on by putting 
"metallic" in the reflection{} block.
It looks like you are, though...the scene looks right to me.
Photons that reflect more than once are goint to get darker and closer 
to red, I think the only way to get what you want is to make the surface 
yellower. Or maybe you could try giving reflection a color...you might 
need to turn metallic reflection off then. As I said though, the scene 
looks right to me as it is...

-- 
 -- 
Christopher James Huff <chr### [at] maccom>

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> Are you using metallic reflection? If not, try turning it on by putting
> "metallic" in the reflection{} block.
>

I am.

> It looks like you are, though...the scene looks right to me.
> Photons that reflect more than once are goint to get darker and closer
> to red, I think the only way to get what you want is to make the surface
> yellower. Or maybe you could try giving reflection a color...you might
> need to turn metallic reflection off then. As I said though, the scene
> looks right to me as it is...
>

I tried the above mentioned variations, but they all didn't turn out
as I expected them to (wanted them to, to be more precise ;)

Well, thanks for your suggestions and insight!

Tim

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html

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