Caustics

Kram1032 · Post by **Kram1032** » Mon May 21, 2007 4:09 am

it should look a tiny bit blueish, due to red-absortion...
what REALLY shoud be, is, that the stuff should appear slighly deformed, due to IoR.

CTZn · Post by **CTZn** » Mon May 21, 2007 6:18 am

That pic looks strrange:
as if this just was a plane with ripples on it.
no thickness -> beyond water, the cubes don't look different from above...

Mmm actually the water is a volume, because unlike you stated Kram you can see the effect of refraction upon the cubes; the water has no absorbtion nor diffraction (cbc) of any sort.

But I think it is heavily postproked

Kram1032 · Post by **Kram1032** » Mon May 21, 2007 7:00 am

that water really has thickness?
it doesn't look at all, like that...

CTZn · Post by **CTZn** » Tue May 22, 2007 5:56 am

It has no thickness; it's filling the whole box, but has no absorbtion nor sss or cbc (its a perfect perfect refractionsceme, like theory in maths), that's why it's not obvious.

Take a vertical edge of a cube from above the surface, then prolongate it and you'll see there is a shift with the same edge under water...

Kram1032 · Post by **Kram1032** » Tue May 22, 2007 6:10 am

that doesn't matter...
if it's filling, it has thickness...
just the IoR wil make it visible and IoR 1 wont give caustics...
strange.

CTZn · Post by **CTZn** » Tue May 22, 2007 6:49 am

Actually there are maybe two planes only: one for the surface and the other for the front pane...

neepneep · Post by **neepneep** » Tue May 22, 2007 8:37 am

oh well here is a version where the water has volume as well as scattering and also slight red absorptivity since I was curious what it would be like. I also wanted to see if using a fresnel lens made a difference, which I think just contributed to making some extra smaller caustics.

My water ripples are a bit crap because I made them with the fractal subdivide operation on a plane in Blender. Does anyone know an easy way to make accurate wave-based ripples?

motorsep · Post by **motorsep** » Tue May 22, 2007 8:47 am

neepneep,

that looks cool

How about having cornell box half filled with water that has volume?

Kram1032 · Post by **Kram1032** » Tue May 22, 2007 8:51 am

simply use bumpmap for hires waves

but else, you can try "stucci" procedual + subsurf + displacement modifier

actually, those waves don't look TOO bad

carbon · Post by **carbon** » Tue May 22, 2007 8:55 am

sculpt it

textured brush (maybe with water texture), to add detail, (not checked if it works)

Kram1032 · Post by **Kram1032** » Tue May 22, 2007 9:09 am

that also should work

But only, if you want to go in DEEP detail.

An other way would be, using the fluid sim.
would give the most realistic result, as long, as the res is high enough.

neepneep · Post by **neepneep** » Tue May 22, 2007 9:46 am

I got a new displacement texture to try BUT filling the box half-way with water as a volume and figuring out where to put the camera is a pain in the ass!

Now I know why people have been using single planes.....

neepneep · Post by **neepneep** » Tue May 22, 2007 12:28 pm

motorsep · Post by **motorsep** » Wed May 23, 2007 1:25 am

neepneep,

wow. awesome!
Would you please describe workflow for that scene and post settings for it and for materials?
Thanks in advance.

Kram1032 · Post by **Kram1032** » Wed May 23, 2007 1:50 am

displacement texture or displacement modifier?
It shouild be easier to use the modifier.
If the texture works at all^^
I don't know, but I also don't think: the actual calculation of mesh deforming is done, AFTER hitting he renderbutton, so it shouldn't be exported...

Can you now make it higher res?
It's pretty small...
What I can see, is that the absorbtion is still too high.
you wouldn't really see the effect, in that depth.
(Btw: How big is the scene?)

Caustics

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