I've been working on an image with a glass-vase
lately (to be found in the images, look at the Gerbera
related images).

I was using photons, and decided to go for dispersion
as well.
But when introducing dispersion to the scene, I get a lot
of artifacts, even when dispersion-samples are set to
50. I'm using a dispersion-amount of 1.02, and I just
wanted to ask if anyone has some experience and can
tell me some general good rules, what amount to use (in
regard to the scale of objects, or what, I don't know what
the value is for exactly) and how dispersion affects the
actual photons themselves.

Thanks in advance!


--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message

Oh, one more thing:

I've got this vase which is used as target for photons.
Thus, photons have to move through the water inside
the vase before hitting the floor.
If I set a dispersion-value for the water, though it is
not a target, will if affect the photons?

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message

> I've got this vase which is used as target for photons.
> Thus, photons have to move through the water inside
> the vase before hitting the floor.
> If I set a dispersion-value for the water, though it is
> not a target, will if affect the photons?

Why is it not a target? The light goes through the glass, then through the
water, then through the glass again. The water should be a target for
photons.

Just my two eurocents...

So long,

Bonsai

Post a reply to this message

Ah, well, when the vase is the target, the
photons are already mapped through the water.
When targeting the water again, I get twice
as many photons as supposed to hit that
specific area.

Bonsai wrote:

> > I've got this vase which is used as target for photons.
> > Thus, photons have to move through the water inside
> > the vase before hitting the floor.
> > If I set a dispersion-value for the water, though it is
> > not a target, will if affect the photons?
>
> Why is it not a target? The light goes through the glass, then through the
> water, then through the glass again. The water should be a target for
> photons.
>
> Just my two eurocents...
>
> So long,
>
> Bonsai

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message

> > Why is it not a target? The light goes through the glass, then through
the
> > water, then through the glass again. The water should be a target for
> > photons.

As long as the water *accepts* photons:

object {
    water
    photons {
        reflection on // probably doesn't matter for this scene
        refraction on
    }
}

then it doesn't need to be a target. I'm sure the water is completely
surrounded by the vase, so any photons shot towards the water would
eventually hit the vase anyway, making it pointless to also shoot at the
water.

As for the photons+dispersion problem, perhaps if you gave some sample code,
we might be able to help more?

- Slime
[ http://www.slimeland.com/ ]
[ http://www.slimeland.com/images/ ]

Post a reply to this message

Well, sample code, hmhm.

You see, all I added was the dispersion_amount 1.01 and dispersion_samples
30 to the vase and water, and a test-line with
radius 8*Spacing when using dispersion.

In the binaries.images you'll find an example image of what I get when
tracing that with a spacing of .001 (very small).

You'll find there that I dropped the dispersion because of RAM issues...

Slime wrote:

> ...

> As for the photons+dispersion problem, perhaps if you gave some sample code,
> we might be able to help more?
>
> - Slime

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message