Thank you Nathan!!

The picture itself is boring, but to me it shows the accuracy of Nathans
patch.

I modelled a fresnel lens wit a focaldistance of 5 units, put a lightsource
at 5 units from it. The result should be, and is a parallel beam of photons.

photons

      gather 30, 100
      radius 0.1, 2, 0.1
      jitter 0.2
  }

 photons {
      density 0.002
      refraction on
  }

It (800 x 600) took about 5 h 30 m to render on a PII 233.

ingo
--
Met dank aan de muze met het glazen oog.

Post a reply to this message

Attachments:
Download 'FresnelPhoton.jpg' (23 KB)

Preview of image 'FresnelPhoton.jpg'

This is pretty cool!

A note about the render time: whenever you have photons hitting almost
parallel to a surface (as you have here), you'll need a relatively high
density (as you have here), which means long render time.

You might be able to decrease the density without losing quality (but
maybe not).

-Nathan

ingo wrote:
> 
> Thank you Nathan!!
> 
> The picture itself is boring, but to me it shows the accuracy of Nathans
> patch.
> 
> I modelled a fresnel lens wit a focaldistance of 5 units, put a lightsource
> at 5 units from it. The result should be, and is a parallel beam of photons.
> 
> photons
> 
>       gather 30, 100
>       radius 0.1, 2, 0.1
>       jitter 0.2
>   }
> 
>  photons {
>       density 0.002
>       refraction on
>   }
> 
> It (800 x 600) took about 5 h 30 m to render on a PII 233.
> 
> ingo
> --
> Met dank aan de muze met het glazen oog.
> 
>  [Image]

Post a reply to this message

I tried with lower density, but even with this one (on 800x600) you can see
the circular patterns of the photons on the outside of the beam.

Oh, and while correcting the position of the "lightbulb", I found that no
photons are gatherd when the lightsource is inside an object with a
looks_like statement.

ingo

Nathan Kopp heeft geschreven in bericht <36ED5912.6B9BA6DA@Kopp.com>...
>This is pretty cool!
>
>A note about the render time: whenever you have photons hitting almost
>parallel to a surface (as you have here), you'll need a relatively high
>density (as you have here), which means long render time.
>
>You might be able to decrease the density without losing quality (but
>maybe not).
>
>-Nathan


--
Met dank aan de muze met het glazen oog

Post a reply to this message

ingo wrote:
> 
> Oh, and while correcting the position of the "lightbulb", I found that no
> photons are gatherd when the lightsource is inside an object with a
> looks_like statement.
> 

Very true.  Hmm... now that you mention it, maybe I should check the
no_shadow flag.  I might also change the meaning of "photons_pass_through"
to let photons go straight through (right now they get refracted).

-Nathan

Post a reply to this message