Caustics Problem

[HHS]

Hi all,

Since some while I noticed a strange thing while trying to render caustics in a pool with Luxcorerender 2.5 or 2.6.
The strange thing is:

With older scenes created with older Luxcorerender 2.3 or 2.4 I can get caustics in Luxcorerender 2.5 or 2.6 when using caustics light cache.

Newer scenes created with newer Luxcorerender 2.5 or 2.6 alpha (Daily builds) I can`t get any caustics in Luxcorerender 2.5 or 2.6. when using caustics light cache.
With the luxcorerender test scenes I can get caustics (as an example setting the DanishMood or HallBench scene under water ) when using caustics light cache.

I watched every tutorial about getting caustics - it doesn`t work when I create a new scene. When using Light Tracing the caustics are only below the water surface, not visible from above the surface. I checked the normals.

I have attached a test scene where I would expect pool water caustics, but don`t get it. Like there is a invisible switch for caustics ...

Any clues what is going wrong here?

[epilectrolytics]

In your file the world background is set to HDRI with no image attached, the white background is blowing out the caustics from the sun.
Once I switch to Sky background the caustics appear:

The lighting system was changed in a previous version, possibly that's why sun + white background works in v2.4 but not v2.6.

[kintuX]

Yup, same here or what

[bdjones]

I have to drop the opacity of the glass below 1 for the caustics to show back through the plane.

[HHS]

In your file the world background is set to HDRI with no image attached, the white background is blowing out the caustics from the sun.
Once I switch to Sky background the caustics appear:
screenshot.jpg
The lighting system was changed in a previous version, possibly that's why sun + white background works in v2.4 but not v2.6.

And that´s exactly what doesn´t happen here. With no HDRi image attached there is no white sky, switch back to Sky background still no caustics
(When I zipped the file, I noticed the HDRi is still too big, so removed them)

[HHS]

I have to drop the opacity of the glass below 1 for the caustics to show back through the plane.

With Light Tracing it seems indeed the case to do so...
But without Light Tracing (but GI cache on) I still don`t get any caustics as I got used to a while ago...

[Sharlybg]

With a proper lighting it work here: https://polyhaven.com/a/veld_fire
Also optimise settings a bit : You can also turn of dispersion for even faster render.

File

CausticsTest.7z

(328.37 KiB) Downloaded 287 times

Render:

[bdjones]

I have to drop the opacity of the glass below 1 for the caustics to show back through the plane.

With Light Tracing it seems indeed the case to do so...
But without Light Tracing (but GI cache on) I still don`t get any caustics as I got used to a while ago...

I'm late to the party didn't see 2.3 and didn't play much with 2.4, I think it needs the Light Tracing on now. Which would speed things up if caustics are not needed.

[HHS]

With a proper lighting it work here: https://polyhaven.com/a/veld_fire
Also optimise settings a bit : You can also turn of dispersion for even faster render.

File
CausticsTest.7z

Render:

untitled.jpg

Thanks- that`s what I got with your unchanged file after hitting the render button:

[HHS]

I'm late to the party didn't see 2.3 and didn't play much with 2.4, I think it needs the Light Tracing on now. Which would speed things up if caustics are not needed.

You usually don`t need Light Tracing for caustics under water- here the underwater Paintings Scene from the example files. I removed volume and dispersions for speeding things up, and I used a hdri here- still I get caustics here and visible from above the water