Iray's dirty little secret...
Cake One
Posts: 382
Hi everyone
Here comes a little secret to speed up your renders in IRAY without any loss.
i have been using this techinque for weeks now so i can garantee it works.
The idea is to render BIGGER but with less passes, to create some manual antialiasing.
I didn't invent it so i won't take the credit here, i'm just happy to share it with you (for the ones who didn't know about it yet)
Here is the infos with exemples and a much better explanation:
http://buerobewegt.com/quicktip-rendering-even-faster-in-iray/
Enjoy
Have a nice day (and nice and fast renders)
C.
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Comments
Dirty indeed!!!!
This has been pointed out before, and yeah -- if your machine can handle the size, bigger is better and then scale down. Eventually the space needed for an image starts becoming a problem.
In 3DL I found it often useful to render bigger, too, because a lot of details and texture patterns render better that way.
Cool... will try that sometime! Thnx! :D
Thanks for the render tip, but what samples ?? Not very explainatory.
Ye im also looking for samples lol. Probably called something else in Studio.
I read the original article, but it is merely indicative of what should be done to achieve a certain result (with useful end-result picts), instead of explicative of what exactly needs to be done, step by step, to actually achieve said results. Maybe somebody could do us the favor of putting together a little "How to do" tutorial with menu and screen shots showing where one has to do what?
I've already tried various combinations of this and unfortunately I didn't find it gave good results. If you stop long before converging to 90%+, sure, you can get quick results. But if you want high quality renders, I find doing the larger renders take more time. And yes, you would stop before getting to 90%. That's the whole point. But it still takes too long IMO.
The render settings, under Progressive Rendering, has settings for Samples, but in the render info window, (click on Advanced to see the updates as they happen,) they are called iterations.
Something else I've discovered that helps marginally, (and I'll take all the help I can get, doing all my rendering in CPU Only,) is to change those parameters so it's only updating every 100 samples. (If you want, you change or remove limits and set that value even higher.) I usually start my renders when I'm heading to bed, and I don't need to see updates. So I let the computer use that time to render, instead of doing constant updates. This value is accessible on the left of the render window, so when I get up, I'll change it to 1 to force a quick update and see how things are progressing, and then change it again to something larger.
cool thx..
Thanks for the link. That little trick will come in handy
Here are the samples (renders settings >Progressive render>4th line: "Max Sample" )
By defaut, Max sample is at 5000.
When i do a render, i double the size with this parameter at 2000 instead of 5000. If for any reason the render is not good enough at the end, i change the value to 3000 and hit "Resume" so the render doesn't start all over again but just implement itself.
@Cake One: that's awesome .... thank you for taking the time to do this. I will be trying it this weekend!
you ve highlighted min samples
Think that was just a screenshot to show where the option is located, where the mouse was on the wrong slider lol. But we can all see where the max is:)
and i ve tried this some month ago and again now
does not work for me
we need much more info to really compare
I'm testing this now....
Render at 900x815 with 5000 samples was 7min47sec.
Render at 1600x1448 with 2000 samples was 9min20sec.
Maybe I need to do more testing, but so far I am not seeing a speed advantage. Need to do more research.
people look more at pics than reading so this could be misleading
Ok
Here is some "proof".
I made a scene, Victoria 7 and 1 light dome from Dimension Theory. I added some jewelry to get some gold and shiny diamond.
There is no Depth of field as my point is to show how more sharp your render can be.
On the left image, i rendered at 800x760, and didn't touch the"defaut" pass : 5000 and let it render till it ends itself.
It took almost 7 minutes.
On the right, i doubled the size and reduced the number of pass to 2000 but at the end, I didn't let the renderer end it itself, i stopped it before at around 7 minutes to be able to compare results on the same TIME (i could have let it continue to have a better render but that was not the point here). In photoshop, i reduced the size by 2 to match the original render size.
Now, click on the image to have it full size with no web browser compression.
See how the left one seems blurry compared to the right one, which looks much more crispy? look at the fingers joints, the lips, the face skin pores etc...
The point here is :
To achieve a certain quality, it takes less time to render twice the size et reduce it later. :)
Try and and even post the results here
Oh I was looking at overall render times to be reduced by half lol. In this case, yes, bigger is faster.
800x800 style renders are taking people 7+ minutes? o.o
I thought I was slow for taking that long to render a 2000x4000 image. 800 is my goto for 1-2min renders o.o
Well, maybe i didn't explain well on the first post.
Same render time : Better quality
We're looking for quality.
In your exemple at 2000 passes, it takes a little more time but i'm sure if you post the result, the quality will be MUCH MORE than just a little bit better.
AND double the size at least. Not just a little big bigger: it's not enough because when rendered is double by size, when you reduce the size by 2 after that, it created a x2 manual antialiasing.
Depends on what they are rendering at that resolution, and what quality setting.
To show the difference in terms of time by render, i made a 3rd render (on the far right) : Size still doubled but render time divide by 2 (i took the original render time and divided that by to)
I asked Studio to stop the render after exactly 164 seconds (as the first render stopped itself after 328 seconds)
You see it's far from being finnished but it shows you it's already sharper than the original render in twice less time.
Sweet. Thanks for the comparison.
I think what you are seeing might be the effect of the automatic texture compression in Iray. Try to disable it for the smaller render, I think you'll find that you'll get the same quality. I can't test it now as I am not at my work station. Basically, Iray automatically reduces the texture sizes if the textures are larger than needed for the current image size.
TD
Is that related to the sizes you set in the advanced options? iirc it's something like 512 min 1024 max by default, but I always put max to 4096 in case it needs the detailed versions for something thinking that it would resize if the figure was smaller, for example.
Yes, that's what I was referring to. I can't test it now but depending on what is set there, you can get compressed textures and that might play into what we see here.
TD
Well as i didn't close my scene in Daz Studio, i'm doing a fourth render with those settings set at 4096 to see what it changes in terms of quality and render time. I'll post it as soon as it's done :)