LuxCoreRender Forums

Hi,

I am a new blendluxcore user and a new Blender user.

I am finding luxcore to be superior to regular cycles when rendering my scene, which is the Roman Pantheon. A challenging scene to light due to the singular circlular opening in the roof, the oculus. I prefer to light with a single HDRI, to get the most realistic lighting.

However, the issue I am having is that when attempting to use caches, photogi indirect and/or environment cache, i have to wait 20-30mins before the render starts, if it starts at all. Is this because of my complexe scene (>100 MTris)? I'd prefer to use the caches, since when it works I see the speed improvement.

Running Blender v2.90, Win10 64bit, nVidia drivers: 452.06
i7 3770k /w 24GB ram, 980 GTX

Update:

I had been using luxcore 2.4 with Blender 2.9. But I just tried the daily release of luxcore 2.5 and with environment light cache only enabled it completed in 2.5 minutes, instead of the 10 minutes with luxcore 2.4, excellent! If I enable photongi it doesn't complete even after 50 mins. =/

nigma46 wrote: ↑Fri Nov 06, 2020 9:36 am Update:

I had been using luxcore 2.4 with Blender 2.9. But I just tried the daily release of luxcore 2.5 and with environment light cache only enabled it completed in 2.5 minutes, instead of the 10 minutes with luxcore 2.4, excellent! If I enable photongi it doesn't complete even after 50 mins. =/

can you show the concerned Cache setting you have ?

Sharlybg: Sure, see attached. I've tried photongi with default settings. It is currently turned off in the screenshot, but i was using default settings.

Reduce your photon count to 2 million instead of current 20 millions.
reduce your brute force radius scale to 1 instead of 8 and try render again.

Brute force radius scale has no influence on the cache building time, it only influences rendering performance after the cache is built.

@OP:
Can you provide a stripped-down simplified testscene that still shows the problem? Try removing textures, replacing high-poly objects with simplified meshes, etc.
Please also mention what kind of hardware you are rendering on.
Another good thing to have would be a log output from the console.

B.Y.O.B. wrote: ↑Fri Nov 06, 2020 11:30 am Brute force radius scale has no influence on the cache building time, it only influences rendering performance after the cache is built.

@OP:
Can you provide a stripped-down simplified testscene that still shows the problem? Try removing textures, replacing high-poly objects with simplified meshes, etc.
Please also mention what kind of hardware you are rendering on.
Another good thing to have would be a log output from the console.

thanks for youre reply. I am rendering with GPU only, a 980gtx card.

I dont have any textures except for blueprints on large planes, these are hidden from rendering in cycles, it seems this setting also applied for luxcore. I could try remove these planes from the scene as a test.

I dont have an easy way to reduce the poly count in my scene other than use the simplify option that exists in cycles, though I have been working if luxcore can read this setting, can it? I think it might as I think I remember setting it to 0 subdivision surfaces for render and thought i noticed reduced polys in luxcore.

Sharlybg wrote: ↑Fri Nov 06, 2020 11:26 am Reduce your photon count to 2 million instead of current 20 millions.
reduce your brute force radius scale to 1 instead of 8 and try render again.

I think I did try reduce photon count, but got light leaks and pre-render calc time didn't seem to decrease much.

Brute force radius scale has no influence on the cache building time, it only influences rendering performance after the cache is built.

yes i know that. i want affect both build time and rendering perf.

I tried to exclude the blueprint "emptys" from luxcore render and set PhotonGI photon number to 1 million. Still did not finish pre-calcs for 15 mins, then I cancelled.