Hello,
Here is an image inspired by a holiday picture. I like it although I find the green in the water reflection at the top is too dark.
However, this took a long time to render with Bidir (default parameters), are there tricks to speed up the rendering (2000*1500px image, 500 samples, 1h 40 min on Intel core i3-6100, 300K tris) ?
Have a good day.
Fabi
Swimming pool / Underwater / Caustics
Forum rules
Please upload a testscene that allows developers to reproduce the problem, and attach some images.
Please upload a testscene that allows developers to reproduce the problem, and attach some images.
Re: Swimming pool / Underwater / Caustics
Hi and welcome to the forum
I have to say first that the image already looks very nice to me
It is usually a good idea to post a blender scene file with your questions so that others can investigate your problem in detail.
Am I right to assume that you have set up a pool of water and your camera is submerged in the water? In that case, the part that is "too dark" is the reflection on the water surface? It doesn't look bad to me at first glance, as your angles could be below total internal reflection. (hard to tell without a blend file )
I have to say first that the image already looks very nice to me
It is usually a good idea to post a blender scene file with your questions so that others can investigate your problem in detail.
Am I right to assume that you have set up a pool of water and your camera is submerged in the water? In that case, the part that is "too dark" is the reflection on the water surface? It doesn't look bad to me at first glance, as your angles could be below total internal reflection. (hard to tell without a blend file )
Re: Swimming pool / Underwater / Caustics
It's so beautiful.
Re: Swimming pool / Underwater / Caustics
Here is the .blend file, so simple.
You are right, the camera is under the water. I agree the green shall be total reflection, but on my reference photo the caustics are also reflected which makes the green brighter.
You are right, the camera is under the water. I agree the green shall be total reflection, but on my reference photo the caustics are also reflected which makes the green brighter.
- Attachments
-
- swimming_pool.luxcorerender.blend
- (827.91 KiB) Downloaded 208 times
Re: Swimming pool / Underwater / Caustics
Caustics seen through perfectly specular reflections are so-called "SDS paths" (specular-diffuse-specular), and Bidir can't render these. You would need SPPM or BidirVM for them, or you could try the new PhotonGI caustic cache in the latest daily builds.
Nice scene by the way, could we make it into an example scene? Are the textures under a license that allows redistribution?
edit: looking into your .blend, the shading on the walls is wrong - enable auto smooth in the mesh options.
Re: Swimming pool / Underwater / Caustics
Aaaah yes, I didn't spot that!
This is because that would be an SDS path (specular-diffuse-specular, here refraction on the water surface, diffuse pool wall and specular reflection on the water surface), which is generally very hard to render for normal ray-trracing algorithms.
Re: Swimming pool / Underwater / Caustics
You can use the scene for your example scenes if you like, with pleasure. The textures come from sketchuptextureclub.com, I don't know about their redistribution policy, the textures I took are free, and you have to register for download.
I will download v2.2 beta to test PhotonGI, and post the result as I got it working.
Thank you for your support.
I will download v2.2 beta to test PhotonGI, and post the result as I got it working.
Thank you for your support.
Re: Swimming pool / Underwater / Caustics
Thanks! I'll replace the textures.
I have played around with the caustic cache a bit, but it's pretty frustrating. You can always see the individual photons, I couldn't figure out settings that fix that.
Anyway, here some pictures that illustrate how PhotonGI can render SDS paths while Bidir can not. I also did a render with the experimental BidirVM engine which can also render SDS paths, but is not in a usable state (you won't find it in Blender for this reason).
I think Bidir + Metropolis is the way to go.
You can try to use the new OIDN denoiser that is available in the v2.2 alpha to get away with less samples.
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Re: Swimming pool / Underwater / Caustics
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Light and Word designing Creator - www.farbigewelt.ch - aka quantenkristall || #luxcorerender
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Re: Swimming pool / Underwater / Caustics
Hi all,
One more question from my side. You said SDS paths are impossible to render with BiDir...
But is it really impossible or just hard to render?
I'm wondering because the images look quite good, what are you missing?
Physics based render is always connected to some patience... remembering older days where such kind of scene took some days to render...
BR
One more question from my side. You said SDS paths are impossible to render with BiDir...
But is it really impossible or just hard to render?
I'm wondering because the images look quite good, what are you missing?
Physics based render is always connected to some patience... remembering older days where such kind of scene took some days to render...
BR
OS - Windows 7 X64
CPU - Intel CORE i7
GPU1 - Variants of notebook card from nVidia
GPU2 - Variants of notebook onboard card from Intel
Lux - Latest possible relaease
CPU - Intel CORE i7
GPU1 - Variants of notebook card from nVidia
GPU2 - Variants of notebook onboard card from Intel
Lux - Latest possible relaease