Tutorial Iray Progressive Render Settings

[IZnoGouD]

DISCLAIMER: THIS GUIDE IS NOT OF MY AUTORY AND, AS SUCH, I'M NOT FIT TO ANSWER ANY QUESTION. YOU CAN VISIT THE ORIGINAL GUIDE CREATED BY SICKLEYIELD

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Iray Progressive Render Settings
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This weekend [Aug 31, 2015] I got a chance to talk to the DAZ 3D developers about the progressive render settings and what they do. Here's some clarification on those settings. I did not know some of this myself until I had a chance to ask this weekend!

The progressive render settings are found in the "Render Settings" tab in DAZ Studio and the "Editor" portion of that tab. The important settings are:

Max Samples: Short version: The Max Samples count is the maximum number of samples Iray will achieve before it stops the render. The default number is 5000. How long it takes to get to 5000 samples varies by what kind of hardware your computer has - it will get to 5000 much faster on an Nvidia graphics card than a CPU or an AMD card.

Longer version, as best I was able to learn from web research: In any kind of rendering, the engine is trying to depict a 3D image as though it were in real space; in real space your eye views all images as continuous, but in the rendered image, the image has to be broken up into a finite number of pixels. The process of sampling is how a render engine tries to compensate for working with those pixels and the fact that visual information "stops" between them, creating the visual artifacts that you probably associate with a "bad" Iray render. But importantly for now, the more samples Iray calculates, the more it can smooth out the 3D space between the pixels into a continuous image without "jaggies" or "fireflies." More samples make a smoother, more complete image.

Max Time (secs): Iray can also be told to stop the render when a certain number of seconds have passed. The default value is 7200, which is two hours.

Important take-away: Iray will quit when it gets to ONE of these two values, normally. If it gets to two hours but has only done 2000 iterations or samples, it will still quit. If you have older or lesser hardware, you need to set the time much higher to get the same samples.

Rendering Quality Enable: If this is set to OFF, Iray will just use the Max Samples and Max Time to determine when render stops. If you want render time to go just based on those, turn this to OFF. If it is off, the Quality and Convergence sliders don't matter.

Rendering Quality: This linearly increases render time each time you raise the number: 2 is double the value of 1, 3 is triple the value of 1, etc. It overrides the time and samples counts. Use this only if you really want to try the "render forever and tell it to stop when I like how it looks" method. Otherwise just leave it at 1.

Rendering Converged Ratio: This is a function of the time and samples counts. I did not realize this until a dev told me, but apparently this is actually impossible to get to 100%, so to avoid errors it's better to converge to 99.9% instead if you want to make sure everything runs long enough without resorting to the Quality setting. I've probably caused myself and other people some crashes with this, and I'm sorry about that.

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[JKnight]

This was written two years ago and I'm pretty sure the information on Rendering Quality is misleading. The Daz forums are the best place for this sort of stuff, even if it can be a bit hard to find.

 

[Haexoi]

It's accurate in how the iRay settings work. If you want it to run and stop on it's own, enable quality of 1 and set to 99.9 converged ratio. It will stop when it reaches it's "converged ratio". Otherwise, I suggest turning quality off, cranking max samples up to like 20000, time up to some very high number such as 72000 and "let it bake". Check on it every now and then and quit when you've decided it looks "clean enough". Shadows should look smooth and not noisy. You can quickly fix noise and fireflies by rendering at a much higher resolution than you need(HUGE memory requirements btw) then lowering the resolution in an image editor for the "final picture". The algorithm used to condense the data into a smaller space will usually clear up the pixel noise and remove most if not all fireflies. Personally, I advise getting familiar with 3delight unless you have a really powerful nvidia card. Iray is more "photorealistic" in how it handles light and daz3d users gain a huge speed boost if they have a quality card that can work with iray. However, getting lighting to look good. Playing with exposure settings on the camera(in the render settings) etc is all a bit harder to work with. In the hands of an amateur, iray will produce shit. With someone skilled at lighting and photography techniques, you can get nearly lifelike photorealistic renders.

3delight is a "biased" rendering engine, so it uses hacks and assumptions to calculate how light would work in the scene. This means it's not as accurate with lighting as iray - but is much faster(hampered only by the fact that it relies on the cpu rather than gpu). Additionally, the rendering engines respond to shaders very differently. Sometimes iray uber(depending on it's settings) looks fine in 3delight, but usually you need 3delight specific shaders. Additionaly, lights made for 3delight(aoa's advanced lights or the uber lights) will not work in iray. With proper knowledge of the engine you're using. Knowledge of some shader basics and knowledge of lighting(VERY important), you can achieve results as good or better than iray(hollywood has done several movies using 3delight). These engines are merely tools with various pros and cons. All but one of the renders I shared on this site were done in 3delight. The iray one had a very different look and was highly detailed, but took 15 hours to render and lots of fiddling with things to get it to a point where I was satisfied with the scene/lighting. The other HD pics took only an hour or two in 3delight and came out with no noise or fireflies.

 

[toolkitxx]

It should be mentioned that sickleyield is a very active user of DAZ and also a provider of assets as well as tutorials on her channel. Most of the stuff she provides is very down to earth and well explained actually

 

[JKnight]

It should be mentioned that sickleyield is a very active user of DAZ and also a provider of assets as well as tutorials on her channel. Most of the stuff she provides is very down to earth and well explained actually

Yes, I agree that Sickleyield has been very active and helpful, I didn't mean any disrepect to her. I don't see much point in putting rendering information here when there's already a good community likely to be more useful to beginners.

There's nothing inaccurate in the guide, but I found it misleading when I first read it. My main problem was with the description of Rendering Quality:

Rendering Quality: This linearly increases render time each time you raise the number: 2 is double the value of 1, 3 is triple the value of 1, etc. It overrides the time and samples counts. Use this only if you really want to try the "render forever and tell it to stop when I like how it looks" method. Otherwise just leave it at 1.

Using progressive rendering changes the behaviour of the renderer. Instead of blindly calculating maxSamples for a pixel it will generate minSamples, then add add new samples up to maxSamples. As each new sample is added it will compare it with the previous samples (and probably its neighbours) to calculate a similarity (threshold) value. If the samples are 'close enough' it will stop rendering this pixel on the assumption it won't get any better with further sampling.

The rendering quality is the threshold for stopping; higher values for this mean that the samples must be more similar before it stops and therefore more samples are generated. The time and sample counts (maxSamples) are still used in the same way as before, but can potentially be overridden by the quality control to stop rendering on a pixel.

The part in the quote about "render forever and tell it to stop when I like how it looks" should really refer to turning off progressive rendering altogether, since it's the exact opposite of what the progressive renderer is trying to automate.

 

[huyvuksxd]

it is hard to give advise.

 

[Deleted member 136796]

I've seen some artists will set their render quality to high numbers like 300.0 and turn their iterations down to like 1000 or 100. It's said to render fast but with higher quality. My settings usually stay on (100 min samples, 15000 max samples, 2.0 render quality and 99.9% convergence ratio) the majority of my images fully render in under 3 hours with some taking 4.5 to 5 hours.

The problem I've seen is that replicating someone else's results is hit or miss with all the factors that go into a scene. For people to say "Well just do this" and claim you'll get the results you want is not real helpful. I think that experimentation is where you'll find the most answers.

 

[obiwan21]

I've seen some artists will set their render quality to high numbers like 300.0 and turn their iterations down to like 1000 or 100. It's said to render fast but with higher quality. My settings usually stay on (100 min samples, 15000 max samples, 2.0 render quality and 99.9% convergence ratio) the majority of my images fully render in under 3 hours with some taking 4.5 to 5 hours.
The problem I've seen is that replicating someone else's results is hit or miss with all the factors that go into a scene. For people to say "Well just do this" and claim you'll get the results you want is not real helpful. I think that experimentation is where you'll find the most answers.

I have tried your settings and like the quality. Do you prefer these settings for full scenes or do you have different ones for say, character portraits with no background?

 

[Deleted member 136796]

My PC renders scenes with HDRI's or no backgrounds really quickly so for those I usually crank the render quality to like 5.0, it still renders in under 30 minutes to an hour then.
I should stress that results are not typical, user experiences may very.

 

[obiwan21]

My PC renders scenes with HDRI's or no backgrounds really quickly so for those I usually crank the render quality to like 5.0, it still renders in under 30 minutes to an hour then.
I should stress that results are not typical, user experiences may very.

No worries. Thanks for the reply I tried your settings so far and have seen some big difference. A lot less to no artifacts from before.

 

[Deleted member 136796]

Something else I do after wards is with photoshop, I open the image and in the filters tab at top I use noise filter, Median and then I use the Sharpen tab Auto Sharpen to bring back some of the details lost by the noise filter, it seems to work well for me.

 

[gamersglory]

Depends on Resolution I'm going with. 1920x1080 9600 max time 10000 Max Samples Noise filter at 1
4K 14400 Max Time 20000 Max Samples Noise filter at 1 or 2 photoshop Apply Despeckle and then Smart Sharpen Always set Quality setting in Iray to 2

 

[143 others]

does using the same saved scene increase the render time exponentially coz the image that would take few seconds to render earlier is now taking whole 5-6 minutes and giving poor grainy results I have also added few models in the same scene but I am rendering only one at a time whats the problem and how o get rid of this plese help
I have a rtx 3070 laptop (legion)