Caustic Render

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Enty
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Caustic Render

Post by Enty » Fri Jan 03, 2020 9:48 am

Hi there!

I've just finished my latest work after an over-night render.
Cross_Caustic.jpg
Initially I wanted to render a caustic shaped like a cross, but since it wasn't easy to position the camera in this case, I then got this idea and it worked out very well.

I hope you like it as much as I do.

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B.Y.O.B.
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Re: Caustic Render

Post by B.Y.O.B. » Fri Jan 03, 2020 6:11 pm

Nice result!
Would be interesting to see the scene setup/geometry behind this :)
The only thing that in my opinion could be improved: the distorted caustics in the lower right are a bit distracting.

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Enty
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Re: Caustic Render

Post by Enty » Sat Jan 04, 2020 11:16 am

Hi B.Y.O.B.
thank you for your feedback.

Here's the scene setup:
scene_setup.jpg
It's actually pretty simple, just the cross itself, a plane that catches the caustics and the objects to create the fill-caustics.
Also there are four very small area light sources below the cross, one for each bar.
I sculpted some beveled edges on it so the caustics would be more interesting and not cast by a perfectly even and planar surface.
And in general all light sources that cast caustics are really small area light sources so the caustics would be nice and sharp.

Here it is without the caustic in the lower right:
cross_improved.jpg
One technical thing: on the left and in the bottom the last pixels are completely white, which I would not expect. Therefore I had to increase the render size by three pixels an cut that off afterwards.

Great thanks also for the light-tracing feature, it's really, really helpful for caustics rendering.

However it appears to me that it doesn't work all right, the caustics seem to be way too bright.
Bidir + Metropolis reference:
caustics_bidir.jpg
Path Cpu + Sobol:
caustics_path_cpu.jpg
Path OpenCl + Sobol:
caustics_path_opencl.jpg
All three use the same linear tonemapping.
It would be super awesome if that could be fixed, because light-tracing is such a great way of rendering caustics.

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Dade
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Re: Caustic Render

Post by Dade » Sat Jan 04, 2020 1:00 pm

If you are using v2.2 there is some light tracing related stuff that has been fixed on under development v2.3 :idea:
Support LuxCoreRender project with salts and bounties

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Enty
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Re: Caustic Render

Post by Enty » Sat Jan 04, 2020 1:02 pm

Yes, I was using 2.2. Thank you for the hint to 2.3, I'll have a look at it.

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