LuxCoreRender Forums

My post was about the handling of light-emitting meshes inside LuxCore. I didn't mean that you should merge the instances.

daros wrote: Thu Feb 18, 2021 1:56 pm X Dade.
Is the parsing process related only to instanced emitters?

Yes, it is.

B.Y.O.B. wrote: Thu Feb 18, 2021 4:28 pm My post was about the handling of light-emitting meshes inside LuxCore. I didn't mean that you should merge the instances.

Sorry for the misunderstanding B.Y.O.B. , thanks.

Dade wrote: Thu Feb 18, 2021 5:14 pm

daros wrote: Thu Feb 18, 2021 1:56 pm X Dade.
Is the parsing process related only to instanced emitters?

Yes, it is.

Thanks!

Dade wrote: Thu Feb 18, 2021 12:06 pm

Sharlybg wrote: Wed Feb 17, 2021 3:24 pm Play with the number in green to increase or reduce instances (Put 150 or 1500 to not process forever)

I'm running the test with 4500 particles. The result is:

Code: Select all

# LuxCoreRender v2.5beta1 2021/02/18 0be225772cddcc30bb7e34ad41b2d5f533618ebb
#
# 82 secs total:
#   [LuxCore][82.654] [GammaCorrectionPlugin] Kernels compilation time: 0ms
#
# 32secs parsing:
#   [SDL][32.150] Scene objects count: 4502
#
# 35secs light preprocessing:
#   [LuxRays][44.217] Total triangle count: 17860024
#   [LuxRays][44.227] EmbreeAccel build time: 9ms
#   [LuxCore][52.774] Light step #1 preprocessing time: 8.54706secs
#   [LuxCore][54.918] Light step #2 preprocessing time: 2.14381secs
#   [LuxCore][74.839] Light step #3 preprocessing time: 19.9207secs
#   [LuxCore][74.839] Light step #4 preprocessing time: 3.69549e-05secs
#   [LuxCore][80.045] Light step #5 preprocessing time: 5.20684secs
#   [LuxCore][80.045] Light total preprocessing time: 35.8185secs

So 82secs before starting the rendering and most of the time is consumed by:

1) parsing (32secs)

2) light pre-processing (35secs)

Actually, with about 18,000,000 of light sources, the numbers are not so sky high. I will look into a way to accelerate the 2 expansive steps but it may be not easy given the innate serial nature of both.

Hi Dade, so the reason why get about 3 minutes and half for parsing+light preprocessing for 32 millions lightsources is probably because we are running Lux under CPU, right?

I think you can optimize it more. Gpu vs Cpu can give you a big advantage.
In my personal project, i will never use this much light at the same time instead i use bigger light with more segments, not the exact same but LuxCore uses every segment as a different light emitter source.
Like in this render, all done with mesh light and just in 120 seconds. Of course, too many lights will take too much time to process.

Strangelly with Cycles there is almost no processing time. With this blend file you can switch to Cycles and see how fast it is : download/file.php?id=9583

I tried a scene with 1.000.000 lights in 3dsmax, and it takes no time to translate, and with 80 sec of rendering is pretty good looking. i used particles as light sources and material light emission. so all lights are cube mesh light sources.

TAO wrote: Fri Feb 19, 2021 10:12 am i used particles as light sources and material light emission. so all lights are cube mesh light sources.

The previous test scene uses a sphere with ~4000 triangles as particle. It is a huge difference when compared to the 12 triangles of a cube.

Sharlybg wrote: Fri Feb 19, 2021 9:59 am Strangelly with Cycles there is almost no processing time. With this blend file you can switch to Cycles and see how fast it is : download/file.php?id=9583

Yes, Cycles starts to render immediately with this scene.