My rendering is so slow and noisy

[Michał Morzy]

Hello guys,

I attached how my render looks after 8h of rendering. My final resolution was 4960x3505 ( quite big, A3 in 300dpi ). I am pretty sure that something is wrong. After many hours of rendering the output is still noisy. Can you help me? I've render it in default settings. During the rendering the Rays/s are about 700-800. Please help! I need the final images soon :)






Full resolution:

https://www.dropbox.com/s/ggls0brwbic3ccm/preview12.jpg?dl=0

[FrostKiwi]

Hello guys,

I attached how my render looks after 8h of rendering. My final resolution was 4960x3505 ( quite big, A3 in 300dpi ). I am pretty sure that something is wrong. After many hours of rendering the output is still noisy. Can you help me? I've render it in default settings. During the rendering the Rays/s are about 700-800. Please help! I need the final images soon :)






Full resolution:

https://www.dropbox.com/s/ggls0brwbic3ccm/preview12.jpg?dl=0

Pls post the scene in question. If you have truely ONLY 800rays/s and this is not a typo, either its a hardware fsilure, incompatibility or a very badly setup scene. Right now I assume it's a typo.
You have almost no lights and the scene is mostly lit by GI rays with simple geo. You might want to increase GI sample ratio, as all the passes you put into AA arent needed.

[Michał Morzy]

My hardware is:

Intel i7-7090K
32GB Ram

The scene is lighten by HDRI map in Environment tab placed in VrayHDRI + There are some ambient corona lights. I was using the standard settings but increasing either GI/AA balance or LSM didn't work. You think that light portal in windows will help?

[FrostKiwi]

My hardware is:

Intel i7-7090K
32GB Ram

The scene is lighten by HDRI map in Environment tab placed in VrayHDRI + There are some ambient corona lights. I was using the standard settings but increasing either GI/AA balance or LSM didn't work. You think that light portal in windows will help?

If your Rays/s are truly 800, only Gaben's miraclen will help you.
Let the scene render for 3 minutes and post the stats page of the corona VFB to confirm the rays/sec or upload the scene rightaway if you eant someone to doublecheck your setup.
Portals only improve sample importance/priority.

[Michał Morzy]

https://www.dropbox.com/s/qvv1vem6pk7iplu/apartament.zip?dl=0 - here is the Dropbox link to the scene. If someone could look at it will be great!

This is how it looks after few minutes of first pass.

[FrostKiwi]

This is how it looks after few minutes of first pass.

I'll take a look at, but there is a bloddy difference between 928 and 928721 ;)

[Michał Morzy]

This is how it looks after few minutes of first pass.

I'll take a look at, but there is a bloody difference between 928 and 928721 ;)

I mean 800-900k :) My bad. I know that normally it should be bettween 1 500k and 4 000k.

[maru]

Adding light portals would definitely help here.

I can see some strange artefacts on the ceiling - overlapping geometry?

How did you add "ambient lights"...?

Are you rendering with internal resolution set to 1? It should pay off in such resolution.

Maybe some of these articles will be useful for you:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000501982
https://coronarenderer.freshdesk.com/support/solutions/articles/5000516729
https://coronarenderer.freshdesk.com/support/solutions/articles/5000501983
https://coronarenderer.freshdesk.com/support/solutions/articles/5000501660

[FrostKiwi]

First of all 300dpi for A3 is not needed, go down to 150 dpi instead. It will speed your render up by a factor of x4. I have an A2 Movieposter test print in 150 and 300 dpi, no way I'm telling the difference apart from futher than 20cm. Consider it, let's stop this stupid rant, shall we?
You scene is setup mainly ok. The noise comes from missing Direct Illumination samples, which should've been generated by from the window area. You ahve an HDRi in combination with very big panes, which results in ultra soft shadows, and therefore in a big big need for sampling. Since you rendered at a high res and with default settings, you didnt sample direct light enough, but sampled the crap out of those edges, who didn't need it.
Your floor has translusency... why would you do that? A wooden floor is not a leaf.
You used a very highres on the floor to avoid tiling I suppose, thus the map is high res in itself, but low res for the individual panels of wood. There are only pixel thick Bumps running across the length of the floor, resulting in a crap load of fireflies, which need sampling. Find a lower res texture in total, but which is higher res for the induvidual panes, thus you will need to tile it.
Either it's a bug opening you scene in a daily build, or you turned off texture filtering - big no no.

Disregarding the lights, the scene renders just as fast as it is supposed to. Turn up the LSM (eg. 10) and the Gi (eg. 32) mult, to sample more efficiently the noise, instead of AA. I'm on dailies, so I have the benefit of the UHD cache, wich speed things up a notch.

There is no such thing as a 7090k, I assume you ment the 4790k, which is exactly as fast as my fx-8350 on 4.6 GHz so you should see similar results, once you turn off the lights and apply my settings. Scene looks good, congrats on that. The difference in bias is small, so I recommend a aggresive Limit on the Max ray intensity (eg. 4)
So you should get an almost perfect image at my res in 20min.

To get Ondra boiling use the Corona speed hack: set max Ray depth to 26, instad of 25.

Adding light portals would definitely help here.

He already did in the scene he posted.

[maru]

Turn up the LSM (eg. 10) and the Gi (eg. 32) mult, to sample more efficiently the noise, instead of AA.

I don't think turning LSM to 10 is a good idea. This would mean 32 GI samples and 320 direct light samples.

I'm on dailies, so I have the benefit of the UHD cache, wich speed things up a notch.

HD cache is good too. ;)

To get Ondra boiling use the Corona speed hack: set max Ray depth to 26, instad of 25.

Yeah, this might work in this scene. ;)

Adding light portals would definitely help here.

He already did in the scene he posted.

Sorry, this scene is too big for me, didn't download.

[Michał Morzy]

First of all 300dpi for A3 is not needed, go down to 150 dpi instead.

The client need it. I don't know on what purpose he need such a res but I had to deliver the result in 300dpi.

Your floor has translusency... why would you do that? A wooden floor is not a leaf.

Yeah, I figured it out during the day. I accidentally put the bump map into to translucency slot. It wasn't on purpose.

Either it's a bug opening you scene in a daily build, or you turned off texture filtering - big no no.

I've read in arcicles on Corona Freshdesk that setting filtering off could help. I was wrong?

The noise comes from missing Direct Illumination samples, which should've been generated by from the window area. You ahve an HDRi in combination with very big panes, which results in ultra soft shadows, and therefore in a big big need for sampling. Since you rendered at a high res and with default settings, you didnt sample direct light enough, but sampled the crap out of those edges, who didn't need it.

How can I help something with that?

Thanks guys for help!

[FrostKiwi]

I don't think turning LSM to 10 is a good idea. This would mean 32 GI samples and 320 direct light samples.

Yes it is a good idea and it does infact result in 300ish Rays/sample, thus we sample the scrap out of that big area with ultra soft shadows.
The alternative isn't exactly great either: wait 100 to 200 passes till it cleans up and waist all that time sampling the freaking lines of the cushion, that are ok to begin with.

So yea, bump up dem LSM (and GI) and have a cleaner result faster I'd say. (at least it worked for me)

I've read in arcicles on Corona Freshdesk that setting filtering off could help. I was wrong?

You risk bricking your normalmaps into shitty squares, which you won't notice until the image is clean. Tiny squares, where there should be curves are not worth the minimal performance gain. Turn up the bias instead, if you want to sacrifice precision for speed.