Any chances to improve render times with volumetrics material?

[Mac3DX]

I'm rendering a 5K image and the render estimate is 4h 30m on an i9 12900K. This is impractical. I don't know what I do, it wouldn't be my choice but I think I'll have to go to another renderer. On Redshift it should take 5 min.

[Aram Avetisyan]

Hi,

This highly depends on the scene and volumetric materials setup you have.
You can try enabling "Single bounce" in volumetric materials to see if there are any improvements.
I would advise enabling a denoiser as well and checking if it does a good job with a noisy render, to cut render times down.

[Beanzvision]

Perhaps this may help?

[davetwo]

On Redshift it should take 5 min.

Yeah right* - I doubt it if you want the same image quality. Whenever I've tried GPU engines, they're fast when they're cutting corners, but once you crank up the samples etc to get an equivalent image quality (esp on glass etc) then the render times get a LOT longer. 5k sounds like a still image - just send it to a farm for the final.

*Not saying it wouldnt be quicker tho'

[Mac3DX]

You can try enabling "Single bounce" in volumetric materials to see if there are any improvements.
I would advise enabling a denoiser as well and checking if it does a good job with a noisy render, to cut render times down.

Hi Aram,
I'm rendering a milk splash, pretty simple image.
 "Single bounce" speeds up for sure, but it screws all of your colors, maybe we should have a field to input a few more bounces? Any tip in order to preserve the colors?
Corona goes very well with all other material parameters, but we have to be honest, this volumetrics feature needs to be improved and a lot in terms of render time. This rules out the possibility of rendering an animation for example.
I always try to keep denoiser around 4%, otherwise no chance to get your image done in time.

[Mac3DX]

Perhaps this may help?

I don't get it, rendering tiles would make it faster?

[Mac3DX]

On Redshift it should take 5 min.

Yeah right* - I doubt it if you want the same image quality. Whenever I've tried GPU engines, they're fast when they're cutting corners, but once you crank up the samples etc to get an equivalent image quality (esp on glass etc) then the render times get a LOT longer. 5k sounds like a still image - just send it to a farm for the final.

*Not saying it wouldnt be quicker tho'

I'm not going to make comparisons here because I find it unpleasant. But GPU handles it in seconds, the only downside I see is still the accuracy in calculating shadows, but for those who don't work with architecture it doesn't make the slightest difference. What I love most about Corona is its usability, a team that strives to develop something that makes the user's life easier. This you make sure no other renderer has.

[Mac3DX]

I love this silence, that is, nothing will be done due to a better performance with these types of materials.

[TomG]

Not sure what you would like in place of silence - somehow further optimizing volumetric calculations would be a large task that would need planning out at least a version in advance (if it is even possible to speed them up), so a request like that is unlikely to ever appear in a version under development where things are planned out already. So a reply on "something is happening" would not appear quickly :)

[Mac3DX]

Not sure what you would like in place of silence? Two options: We're aware of it and we are doing our best to have it as soon as possible or there is no plan for that in the future due out of interest from users. (Which I think it is not likely)
You know what impresses me the most? No one bothers about it. In my opinion, that was supposed to be in the plans. Please look at available technologies. RS and Cycles have adopted the Radom Walk and it looks really good and fast to me. What we have today is very slow in terms of rendering time making the animation work unfeasible.
I believe that the perfect solution is far from happening, but I also think that a slight improvement should not be something so complex. One step at a time.

[TomG]

But the answer is neither of those things, the answer is "We don't know til we assess what we'll be doing in the version of Corona after this one" - so since there is really no answer yet until a few months when we look into plans for Corona 11, there isn't anything useful to say that is either yes, no, or maybe. We do check all these comments and requests, but it may be days, weeks, or months before we can say something that actually adds information on what is happening :)

[Stefan-L]

on a side note: As far i see from Maya/Houdini Chaosgroup announcements for V-Ray, V-Ray 5 added random walk some time ago in the new Subsurface scatter in in the new vray 5 material.

as vray 5/6 and corona 8/9 share a very similar material setup/features (mostly only different gui), i thought the new SSS also on Corona is random walk based?
i might be wrong of course, maybe the Corona team can answer that?
i also think random walk is nothing special fast if calculated precise. (maybe faster on gpu of course)

overall in RS p.e. some parts render fast for sure being gpu based, but other stuff and gui, like having just a few big 8k textures bring it here down to be very slow(2080ti), material previews are super slow, etc.
so i think which engine suits best very much depends what one needs, depending the type of work.
for me corona is still by far the winner for archviz at least.

what i woudl hope most is speed up of DOF, here vray is much faster yet with almost no speed hit, while in corona it seems to cost much extra time (while slower in other parts)

[burnin]

Personally, I'd love to see and tackle with the scene in question...

[Mac3DX]

Start with this one, I'd love to have a 4k image in 20 min to be reasonable.

https://forum.corona-renderer.com/index.php?topic=38612.msg206820#msg206820