PhotonGI caustic cache re-factoring

[Dade]

I added the support for OpenCL.

[Dade]

Are you sure that caustic cache works with volumes?

It didn't seem to me in my scene, so I made a simple test case.

BiDir + metro:
CCvsVol-bidir.jpg

PT Sobol + Light Tracing:
CCvsVol-lt.jpg

PT Sobol + Caustic Cache:
CCvsVol-cc.jpg

Light tracing (or the cache) is used only "under" the sphere because the caustic is only there, over the sphere, normal path tracing will be used and your light source is very hard to find for a path tracer: just render with normal path tracing to have an idea.

About the cache, the problem is here:

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[LuxCore][0.613] PhotonGI visibility lookup radius: 0.0169757
[LuxCore][0.613] SceneVisibility trace thread count: 12
[LuxCore][2.121] SceneVisibility hit rate: 0.2408%
[LuxCore][2.153] SceneVisibility total entries: 1063240

The scene visibility has an hit rate of 0.2408% but this isn't really surprising: you are trying to cover an infinite 3D space with cache entries. Your volume is the world default and you have an open scene

The cache can cover only a finite amount of space, try to enclose your scene in a box or to use a box volume

[lacilaci]

The scene visibility has an hit rate of 0.2408% but this isn't really surprising: you are trying to cover an infinite 3D space with cache entries. Your volume is the world default and you have an open scene

The cache can cover only a finite amount of space, try to enclose your scene in a box or to use a box volume

Product design showcase might often be happening in a very open scene, can't we have bounced photons killed once they exit scene bounding box? Wouldn't this help focus cache where it needs to happen?

[Dade]

Product design showcase might often be happening in a very open scene, can't we have bounced photons killed once they exit scene bounding box? Wouldn't this help focus cache where it needs to happen?

The above scene bounding box is really small (i.e. it would truncate the visible volume scattering under the sphere, with no volume caustic at all). However this is a quite corner case: the use of default scene volume imply a infinite scene size, this is somewhat incompatible with using a finite (volume) cache.

[evacnoc]

Hi,
I'm new to Luxcore and just started testing the last build.
What settings should I modify to get light passing through water plane when the camera is below it?

[Dade]

What settings should I modify to get light passing through water plane when the camera is below it?

You have to set the camera volume to "water" otherwise the ray will start with default scene volume (I assume it is "air"). In general, you have to be careful setting up the object volumes or you can end with some odd result.

[Dade]

I have added the option to use the caustic cache only for SDS paths:

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path.photongi.caustic.useonlyforsds = 1

And this is a rendering with Hybrid forward/backward path tracing and caustic cache used only for SDS paths:

This is some serious beauty

[lacilaci]

I have added the option to use the caustic cache only for SDS paths:

Code: Select all

path.photongi.caustic.useonlyforsds = 1

And this is a rendering with Hybrid forward/backward path tracing and caustic cache used only for SDS paths:


sds.jpg


This is some serious beauty

Oh, yes...
Can I assume that since cache is sds only it will be faster?

[Sharlybg]

This is some serious beauty

What an achievement you have done so far

Can I assume that since cache is sds only it will be faster?

This need to be benchmarked.

[Dade]

Can I assume that since cache is sds only it will be faster?

What do you mean ? Faster compared to ? The cache look up is done only for SDS paths so there are a lot less cache look up (I assume you mean this). However the cache creation time (and update) is exactly the same (a caustic is a caustic and I can not know if it will be seen trough a specular surface or not).

This is a v2.3 manifesto:

If you remove glass dispersion from the first one, you have a Cycles rendering