LuxCoreRender Forums

Hi guys.
My scene have a water surface, and a simple plane beneath it. I want to render caustics, and I want to see the caustics effect through the water, but it´s not working. It seems that water object is blocking the view.
I,m using Lux 2.4 on Blender 2.83.12.

You can enable the Caustics Light PhotonGI Cache to see caustics through reflections and refractions (Specular-Diffuse-Specular paths).

You can tweak the parameters depending on what kind of clarity you want. The default settings were a little blurry, so with some small adjustments, I got a fairly clear result:
P.S. I think you forgot to enable Shade Smooth on your water mesh For the render result shown above, I have enabled Shade Smooth.

Also don't forget to check out Sharly's awesome tutorial on this topic (and many more)! https://www.youtube.com/watch?v=wf-jVYvX8D4

@Martini, thank you very much!
I confess I still have some questions about cache. Other render engines call "cache" something that stores light to reuse in animations, for example. But in Lux, I noted that caches have more functions.
Thank you, again!

Leandro Oliveira wrote: Wed Feb 10, 2021 3:54 pm Other render engines call "cache" something that stores light to reuse in animations, for example.

That is also true of LuxCore. The box at the bottom under Persistence (Compute and save) does that. Check that box. Once you have your parameters how you like it, un-check it. The next time it will be faster to start because it can load the pre-computed cache data from the file.

And yes, if your lights and objects do not change or move during the animation, you can re-use it for each frame, too, even if the camera moves. However if the objects are animated, you should not re-use the cache for different frames.

Leandro Oliveira wrote: Wed Feb 10, 2021 3:54 pm Thank you, again!

You're welcome! Also, nice job on the water, the caustics look great! I can't wait to see what you do with it

Martini, in fact, this is a job of a friend of mine. I was trying to help her. But I´ll ask her if I can show her final job, when it´s done.

Martini, sorry for bother you with this subject, but could you take a look in the attached file? I started a new file and I did the same setup, but this time, it´s not working...

Leandro Oliveira wrote: Fri Feb 12, 2021 12:19 am I started a new file and I did the same setup, but this time, it´s not working...

From what I can tell, viewport renders do not use photons from the PhotonGI cache. To see them, you need to press F12 and do a full render.

Click under Persistence the checkbox Compute and save and choose a file path next to your .blend file. Then press F12 to start a render. You don't need to finish the render, you can stop it as soon as you see pixels appearing. Then you can uncheck the box and your future renders will read photons from that file. (Only full renders, still not viewport renders, sorry)

Thank you, man. We think there´s some bug, but I´ll ask her to post here, and explain better.
Thanks for your help.