Denoiser makes noise?
Leonides02
Posts: 1,379
in The Commons
I'm noticing something odd.
Here's my render at 5,000 iterations with the denoiser ON (but prior to denoising, which was set at 7,000):
Now here's my render at 1,000 iterations with the denoiser turned OFF:
Anyone else seeing this weirdness?
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I've had all kinds of intermittent issues withthe denoiser since 4.11 was released. I had been using the 4.11 beta denoiser without any issue for months.
Likewise. Right now I'm generally using the Intel denoiser after the render because it's non-destructive.
I didn't get 4.11 yet but I see some discussion here about slow rendering times and fireflies that didn't happen with 4.10. Your first render may indeed look like a lot of fireflies. You may try to set the nominal luminabce to 100-200 and see if things get better. But this way you will lose contrast on highlights.
Then if the fireflies happen only with the denoiser on, as in your example, then I guess this new denoiser feature is more a bug than a feature. And using an external denoiser as you suggested would be the only reasonable option.
EDIT. To get a fair comparison you need also to check 1000 iterations with the denoiser on, since it may be that the fireflies happen later in the process.
It may also look like some caustics are growing, and if this is the case then it may be the intended behaviour. Then the problem with caustics will be to let them converge enough to be acceptable. A slow caustics convergence would indeed explain the new fireflies in 4.11.
Yeah, the fireflies only happened when the denoiser was on. Very strange.
please also see my edit above
I ended up rendering the scene without denoiser up to 5,000 and no fireflies appeared.
I would use the external denoiser from intel (for free). It just works better, just do a search on forums! Also a fellow user has created a drag and drop interface for it as well. Iray without good knowlege on how to light a scene will be a firefly mess instead of spending hours working on your light just use free intel denoiser it works great!!!
Silver Dolphin, we are well aware of the external denoisers thank you. Trying to understand 4.11 issues is another thing and may be useful as well.
EDIT. And anyway the intel denoiser is quite a mess with details since iray can't generate the albedo buffer.
The denoiser does work and did work in 4.11 prior to the public release. I used it for almost every render I did for months. There is some weirdness with the public release vs. the last public beta which is simply baffling.
I just ran a set of test renders to see if I can find a sweet spot between iteration count and denoiser settings. I tested at the denoiser running at 50 and 100 iterations and found that they all looked really good with the normal amount of early iteration noise and fireflies. I am using simple lighting with no structures for light ti have to bounce through. I can't post the images here because they are pictures of naked ladies. (I am a pinup artist, after all.)
@Kenshaw011267, do you mean the 383 beta is not the same as the public release ? Also do you mean that the fireflies do not happen in the beta ?
Didn't know about the drag n drop.
Got a link?
https://taosoft.dk/software/freeware/dnden/
Did you happen to be using canvases (canvases on)? I had this sort of experience several versions ago but have not tested again since to see if it remains. Basically the denoiser does not get along with canvases in a very bad way or did.
@Silver Dolphin " Iray without good knowlege on how to light a scene will be a firefly mess instead of spending hours working on your light just use free intel denoiser it works great!!!"
If you don't take the time to understand lighting, you will have a noise free render that isn't worht looking at.
Unless they've made some changes, I don't believe that the integrated denoiser makes use of a reference albedo either.
(I'll admit, I haven't bothered using it since a couple of betas back, as I found it too destructive and that I preferred doing the denoiser as a post-render step in order that I could mix and mask the results in Photoshop).
The way you light a scene for efficient ray-tracing is not inherently the same as the way you might want to light a scene for an aesthetically pleasing result.
I've taken photographs where trying to light a digital scene that way would be horrendously inefficient (sometimes to the point that despite the incomphrensible speeds at which real-life calculates lighting, it still took shutter speeds in multiple seconds to get a clean photo), but where the results just look fantastic.
I'm saying that the lest version of the public beta that was available when the public release happ3ened is not the same version as the public release. I don't have the version numbers.
@kenshaw011267 the beta is still available for download, and in the 4.11 discussion the daz team confirms that the 383 beta is the same as the 4.11 general release.
They are wrong. I can prove it really easily. In the last public beta the denoiser worked properly and without issue when I ran Renderqueue over night. in both the public release and the new beta the denoiser never triggers.
This has cut me from producing 6 to 8 completed render per day to 2.
I haven't tried the denoiser in 4.11 and don't know if I will I've had better results using the intel denoiser.
Yes, I was using canvases because I wanted an HDRI output. It's odd it doesn't work well with canvases. The standalone does fine with HDRI.
I have seen the denoiser in studio always trigger if the viewport is set to iray review prior to rendering. If it's set to texture shaded it seems the denoiser sometimes does not kick in. But sometimes it does. Maybe this is something you are also experencing. This would be a bug if you are also seeing it.
I hardly ever use Iray preview. For me the denoiser triggers every single time if I manually start the renders but never triggers when I use the plugin to do the renders.
Denoiser is an AI denoiser... It works up to a point, until there is nothing left to display for "quick view". At the point where you see noise introduced again, you have literally replaced all the "fake" AI "guesses", with "real values", and you are adding more real values to that scene with each new iteration.
Your denoiser should be set to kick-in earlier than 7000 iterations. At 5000 iterations the denoiser hasn't even started, so it's not the source of noise. By that point, at 7000 iterations, there is honestly nothing left to "guess" in the scene, almost all values are absolute and "rendered".
The noise you see is stray refractions and reflections from the light beaming through the window and onto the wall and back at the camera. Micro-surface bumps. Most-likely due to the use of a noise-map, bump-map and/or non-linear refractions from the glass. (Or caustics, which makes more realistic light by doing the non-fast light calculations that IRAY has OFF, by default. Instead, using less accurate linear fast calculations that don't diverge from the source through refractions and sub-surfaces and atmosphere/falloff diffusion.)
Denoiser is intended for early-termination renders, not final renders. At some point, all the guesses are gone and there is nothing left to guess anymore. You want a post-denoiser.
The best use for denoiser is for animations, where you can only render each scene for something like 500 iterations and NEED as little noise as possible. Quality and micro-detail isn't as much of an issue on something that is animating and moving across the screen. (IRAY doesn't have adaptive motion denoiser setup YET... That would look per-scene, and determine if more or less render-time was needed, if a scene had less motion, as opposed to more. But, there is a plugin for that. Just not one for IRAY in Daz, at the moment.)