It’s a nice scene, congrats on your high placement in the voting (still ongoing at the moment).
Below are some tips, I hope they help. And I hope it’s not too overwhelming
The following caches are not useful in this scene and should be disabled: DLSC, Env. light cache, indirect light cache. This saves a lot of startup time.
Light tracing is enabled, but with a glossiness threshold of 0.049 it is not used for the dice materials because they have a roughness of 0.05. You can raise the threshold to use light tracing for these caustics.
I also changed the light rays percentage to 100% because I’m rendering on both CPU and GPU (CPU does 100% light rays, while GPU does the rest). If you render on CPU only, you might want to change it back to something like 50% or so.
In the caustics cache settings, I would disable “periodic update”, because the caustic cache entries are only seen through very rough glass in this scene, so the first pass is good enough and we can save the performance penalty of rebuilding every x samples.
To reduce the noise variance I also enabled clamping.
I raised the sampler’s adaptive strength from 0.5 to 0.9 so it focuses more on noisy parts of the image.
(the default should probably be a bit higher).
Even after the corrections mentioned above, the scene is not the fastest, this is just due to all the rough glass requiring a lot of brute force - clear glass would clear up much faster.
Side note: you are using the transmission color to color the glass, this is not physically correct, it would be more accurate to use a clear interior volume with colored absorption (you can use the “colored glass” preset in the material property panel as an example).
Here is the fixed file: dice-luxcore_b.blend (2.6 MB)
Open with BlendLuxCore v2.3rc1 or later.
(you’ll have to fix the textures of the two dice, I changed them to textures that were packed in the .blend because they were missing)
And the rendered results:
(1000 samples, 6 minutes on RTX 2080 + Ryzen 7 2700x)