LuxCoreRender Forums

Still I'm designing a 80sqm appartement and just started with the bathroom.
Again, i just have to say WOW concerning LuxCoreRender- I don't know any other render engine for Blender handling Caustics that well.

Any advices to make the best use of Light Tracing? I had it at 100% CPU usage and it made a lot more samples as path tracing. Is it useful to give some CPU power back to path tracing? And how to adjust the roughness threshold properly?

Anyways, I hope you like the result.

It's rare for CPU light tracing to be faster than a 2080 Ti in my experience with an i9 9900K and 2 2080 Tis But yes, if that is indeed the case, you could scale some CPU power to path tracing also. Does your scene and textures require more than 10GB memory so that you have to use out-of-core rendering?

If you actually meant to say that path tracing was way faster than light tracing, you could set the halt condition based on light tracing samples instead (new feature of LuxCore 2.5).

Also, if you have got your caustic cache radius set how you want it, you can speed up rendering by disabling the automatic updating reduction step and just force it on the minimum size right from the beginning, and it won't waste time re-shooting caustics during rendering.

Martini wrote: ↑Fri Mar 05, 2021 6:24 am It's rare for CPU light tracing to be faster than a 2080 Ti in my experience with an i9 9900K and 2 2080 Tis But yes, if that is indeed the case, you could scale some CPU power to path tracing also. Does your scene and textures require more than 10GB memory so that you have to use out-of-core rendering?

Actually i have this in all of the appartement shots so far. Light tracing is way faster. But after some hundred samples, path tracing is getting faster an closing the gap. But i don't need that many samples, when rendering in high resolution, because the denoiser works awesome.
Memory is just about 6.5GB and so i don't need OOC rendering. Cache friendly however seems to be pretty cool for a good rendering performance.

Should the ratio of light tracing / path tracing be equal?

Thanks for your advices. I didn't know about the speed up when using a constant lookup radius with the caustic cache. Will try that immediately.

johannes.wilde wrote: ↑Fri Mar 05, 2021 7:06 am Should the ratio of light tracing / path tracing be equal?

Ideally, for "equivalent" quality, yes. But it should not matter if there are extra samples in one or the other, it just means quality will be higher there (or you could think of it as performance "wasted").

johannes.wilde wrote: ↑Fri Mar 05, 2021 7:06 am Actually i have this in all of the appartement shots so far. Light tracing is way faster. But after some hundred samples, path tracing is getting faster an closing the gap.

That is weird for me. Perhaps because I have 2 2080 Tis, I never saw the CPU even come close. But perhaps the AMD CPU solution is better than Intel there somehow? I always suspected this would be the case for ThreadRipper-class CPUs, although yours is "only" 8c/16t...

johannes.wilde wrote: ↑Fri Mar 05, 2021 7:06 am Memory is just about 6.5GB and so i don't need OOC rendering. Cache friendly however seems to be pretty cool for a good rendering performance.

Yes, definitely.

johannes.wilde wrote: ↑Fri Mar 05, 2021 7:06 am Thanks for your advices. I didn't know about the speed up when using a constant lookup radius with the caustic cache. Will try that immediately.

No problem! Best of luck! Also, your bathroom looks amazing

Martini wrote: ↑Fri Mar 05, 2021 6:24 am Also, if you have got your caustic cache radius set how you want it, you can speed up rendering by disabling the automatic updating reduction step and just force it on the minimum size right from the beginning, and it won't waste time re-shooting caustics during rendering.

That renders super fast, but if i have a larger radius, i get these light blobs and if i set the radius small, the caustics look like pure noise.
Any tricks for that. A lot more photons to shoot?

johannes.wilde wrote: ↑Fri Mar 05, 2021 1:02 pm That renders super fast, but if i have a larger radius, i get these light blobs and if i set the radius small, the caustics look like pure noise.
Any tricks for that. A lot more photons to shoot?

Yep, you guessed it right

More Output from today

Progress from today.

Wow, that looks incredible! I once stayed in a hotel that was converted from an old army barracks, the stone material reminds me of that - except yours is way more fancy with the glass windows They look so good!

IMHO the bevel on the sink basin looks pretty tight, you might cut yourself on it