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How to reduce a Liquigen sim rendering times.

Posted: Wed Apr 23, 2025 5:49 am
by Jukyan
Hi there,

I have to render a quite big water simulation done in Liquigen.
The built-in Liquigen render engine would be good enough for what I need but I need to render with a spherical camera, so I would render it in C4D+octane.

Problem is... switching to octane takes more than... 2min per frame ! (resolution is 6800x3540)
Liquigen renders in less than 2seconds per frame !
I am wondering why there is such gap between Liquigen & Octane. I just need a simple water shader with a reflection/refraction, no GI or HDRI required.

Does anyone have tips on how to simplify the rendering to the lowest possible rendertimes ?
Or how to render in another app or render engine entirely, who would use GPU rendering & spherical cameras, matching the look below.

Also another problem is : the first frame renders normally, then the rendering time increases significantly over the following frames...
Seriously... WTF ?!
Image
I won't consider online rendering because the sim file would take a whole day to upload with my bandwidth...



Thanks in advance !
Image

Re: How to reduce a Liquigen sim rendering times.

Posted: Wed Apr 23, 2025 7:53 am
by bepeg4d
Hi,

please share a screenshot of Kernel Settings panel.

Maybe you can speed up a little the render time per frame, but I suppose that a 240GB liquid sim at almost 8k resolution cannot be fast to be calculated, and you need a lot of GPU power.

ciao,
Beppe

Re: How to reduce a Liquigen sim rendering times.

Posted: Wed Apr 23, 2025 6:49 pm
by Jukyan
Too bad there isn't a "biased speed rendering" option for octane :p

In this case it doesn't make sense to render with an unbiased engine but thats all I got... :/

Here are my settings :
Image

Re: How to reduce a Liquigen sim rendering times.

Posted: Thu Apr 24, 2025 7:26 am
by bepeg4d
Ok, you cannot increase the rendering speed to much, but try these settings:

- Path termination power = 1
- Parallel samples = 32
- Max Tiles = 64
- Noise threshold = 0.05
- Expected exposure = copy-paste the Exposure value from Camera Imager node
- Group pixels = none

ciao,
Beppe

Re: How to reduce a Liquigen sim rendering times.

Posted: Fri Apr 25, 2025 10:42 am
by Jukyan
Thanks Beppe !
These few % difference will help & save a couple hours ;)

Re: How to reduce a Liquigen sim rendering times.

Posted: Mon Apr 28, 2025 7:33 am
by bepeg4d
Great!

Happy GPU rendering!

ciao,
Beppe