DAZ IRay Render Speeds
Catalyst
Posts: 27
I have a general question about render times in IRay.
Basically, I have my first IRay render going now, it's not that large (877 x 1240), and it's been running almost 11 hours now, and it's still very grainy, and only on IRay iteration 11 (0%). So about 1 iteration an hour.
I know my machine is substandard (the same picture at twice the rez (1754 x 2480) took 16 hours in Reality 4 - and that was only 500 passes). I'm only running with one dual core and an Nvidia GeForce GT 625.
So I guess I'm really wondering wondering how substandard my machine is. What are the average times most people are seeing? It's a relatively simple scene, one character (admittedly wearing a lot of layered clothing) and a stained glass window as the background (the window is simply a 2D image set in a simple wall - it's not rendering as glass or anything). I converted all the shaders, and replaced them with IRay presets when possible (what I see so far does look great). There are no lights in the scene at all, headlamp is set to 12%, included sky & dome set to 6:30 PM - that's it.
So how unusual are these times? Based on what I've indicated am I clearly doing something wrong?
Any feedback is welcome.
Thanks!
Daz 3D is part of 
Connect
DAZ Productions, Inc.
7533 S Center View Ct #4664
West Jordan, UT 84084
Licensing Agreement | Terms of Service | Privacy Policy | EULA
© 2025 Daz Productions Inc. All Rights Reserved.
Comments
That sounds about right to me.
I guess the main problem is that when a scene is too big for the GPU, the GPU is switched off and you get no contribution from it.
Did you change the Iray settings to go beyond the 2 hour limit?
I know I've been having some problem with Iray not stopping when it hits it's first default stopping mark (2 hours or 92% might be 98%)
If you haven't changed any of those settings, then Iray might be stuck (which means it won't make any more passes even though the timer is still counting)
Time limit, you say?
I'm using all the default settings, that said it's been running another two hours now and hasn't progressed at all. I'm going to stop this render and look for this "time limit" setting (wish I'd seen that before). I kinda hope it's locked up, that would at least explain why the picture quality doesn't seem to be improving.
Ok, I changed the time limit from 7200 secs to 7201 - hopefully it will register the setting now that it's not the technical default.
Thanks to both of you!
Yes, there are 3 settings in which you can change and the render is supposed to stop when it hits the first of those 3 settings. but as I said, lately I've been having problems with Iray not closing after hitting those conditions.
I realized that when my screen went to sleep the my computer rev'd down significantly. Went and watched the IRay renderer, which diesn't seem to be progressing again. Set monitor to never sleep - restarting the render.
Let you know if, by some miracle, that works.
It is possible that it is sticking. I have an aged computer and can only use CPU and that sounds like a really long render to me. I'm wondering about intersecting transparency's. That seems to cause sticking with Iray currently. Is it possible some of her clothing is intersecting and causing issues?
Yes, that's a definite possibility. She's wearing several overlappin layers of clothing with various parts having their opacity set between 0 - 50%.
I'm really not sure how to fix that - it's kind of the main component to the picture.
It did go right past the 2 hour mark without stopping, and it never passed 30 iterations. I'm kinda sorry I spent all that time converting textures, since it looks like I'm going to have to go back to DAZ 4.7 & Reality if I ever want the picture to finish.
Weirdly, I just told mine to render of the CPU only, and not use my video card - and it's rendering a whole lot faster. I'll let you know how it goes I guess. :)
Ok - well apparently the thing for me to do is load an .hdr in the environment map, change it from an infinite sphere to a finite sphere with ground, add a distant light where I want the sun to come from. Voila - 14 minutes later and I am 46% completed.
I'll let you know if I've just jinxed myself.
As I understand it (and on this I am shaky ground) two things can help speed up a render. One is more lights and the other is not having an infinite space unless you really need it (landscapes for example). When I am doing a really simple render, a person with just a backdrop for example, I stick a big box around it all and render it as a scene. That way the light has limits to how far it bounces.
Hm, as far as I know from Luxrender, "boxed" spaces take longer to render than infinite spaces. A light beam that travels to an infinite target is terminated immediately and no longer calculated. In a "boxed" space, all the light beams bounce. And bounce back, and bounce and bounce... I dont know if Iray works in the same way, but since it is a PB unbiased engine, it should behave like Luxrender. So if you want to save render time, do not "box" your scenes.
I also do not understand why more lights should render faster than few lights. I mean, every light source emits light beams that have to be calculated and every light casts shadows that have to be calculated. So every light source adds calculations and therefore render time. Not?
But one thing is true. A well lit scene renders faster than a too dark scene. Thats because a well lit scene "clears up" faster and is less grainy, so a well lit scene needs less iterations to look good and clean. But well lit does not necessarily mean more light sources. In fact the opposite is true. Due to PB calculations you generally need less light sources with an unbiased render engine like Iray, compared to a biased one like 3Delight to get a well lit scene.
i was able to purchase 2 gtx780 video cards from nvidia. That gives me a total of 4600 cud cores. That is about 15 times faster than CPU rendering. So a 2 hour render would take about 8 minutes. But typically most of my render takes under 2 minutes. I have only v6 with some clothing, i'm looking at almost real time rendering. Now that is truly amazing.
This is why nvidia, gives iray out for free. They figure people will invest in new cards. I had the cards from before, so i was lucky. But even so, if I spend more than 10 hours of week with daze, think it's worth $400 to $1000 invest for new video cards.
nick
I'm not sure if this is the place to ask, but i don't want to clog up the forums by making a seperate post of it:
My current video-card is an Nvidia GTX 550 Ti (1 Gb VRAM, 192 CUDA cores), and Iray render times are... let's say "Glacial" ~_~
As a result i'm looking to get a new video card, and i'm liking the look of the Nvidia GTX 960 (2Gb VRAM, 1024 CUDA cores, and also important: affordable, Daz3D rendering is a hobby for me and content is expensive enough already :P ), is that card any good? I have read reviews, but those focus on gaming as far as performance goes and as such don't really help me (I also do gaming, but the main reason to upgrade is Iray rendering)
Also: i have read that if a scene is too big for the VRAM, if causes trouble when rendering, is there any way to see how much video memory a loaded scene takes up?
Hm, as far as I know from Luxrender, "boxed" spaces take longer to render than infinite spaces. A light beam that travels to an infinite target is terminated immediately and no longer calculated. In a "boxed" space, all the light beams bounce. And bounce back, and bounce and bounce... I dont know if Iray works in the same way, but since it is a PB unbiased engine, it should behave like Luxrender. So if you want to save render time, do not "box" your scenes.
I also do not understand why more lights should render faster than few lights. I mean, every light source emits light beams that have to be calculated and every light casts shadows that have to be calculated. So every light source adds calculations and therefore render time. Not?
But one thing is true. A well lit scene renders faster than a too dark scene. Thats because a well lit scene "clears up" faster and is less grainy, so a well lit scene needs less iterations to look good and clean. But well lit does not necessarily mean more light sources. In fact the opposite is true. Due to PB calculations you generally need less light sources with an unbiased render engine like Iray, compared to a biased one like 3Delight to get a well lit scene.
More lights do render faster, I don't know the mathematical reason why; but we've tested this enough to definitely confirm it.
My experience is that "boxed" spaces are indeed slower, and this is part of the reason why using an HDR is much faster than using a skydome/box/sphere.
Did you turn on OptiX acceleration in your render settings?
No. What is this setting good for?
No. What is this setting good for?
It turns on the Magic Go Faster button.
Not really, it's the Opti X very fast ray tracer. It speeds up most renders. I'm not sure why they made it optional.
It turns on the Magic Go Faster button.
Not really, it's the Opti X very fast ray tracer. It speeds up most renders. I'm not sure why they made it optional.
Oh, good to know. I will try it when I use Iray next time. Thank you!
Actually, Nvidia isn't giving away Iray for free. DAZ 3D paid for the license to include Iray in the free DAZ Studio, just as they paid for the license to include 3Delight. I'm sure Nvidia is being paid quite a lot.
Actually, Nvidia isn't giving away Iray for free. DAZ 3D paid for the license to include Iray in the free DAZ Studio, just as they paid for the license to include 3Delight. I'm sure Nvidia is being paid quite a lot.
Iray in DAZ Studio is a new level of development
a very important step that will change a lot
for Nvidia is also very beneficial Iray for many years remained not demanded
now directed at him glances users DS )
Iray in DS it really awesome thing! )
We already have Reality/Luxus to Luxrender and we already have Octane. Both PB unbiased render engines. Iray is just another one. Ok, it is free to use and integrated into DAZ Studio. But therefore it is tied to special kinds of hardware to unlock its full potential. So I really cannot see that big improvement or awesomeness with Iray. And I will definitely not spend a lot of money for a Nvidia GPU when I can use 3Delight and Reality/Lux which I already have and which are not tied to a special brand of hardware.
Oh, and for all Reality/Luxrender useres, please read this: http://preta3d.com/sneak-peek/
A really important step that will change a lot. An awesome thing :-)
...which is tied to special hardware.
...which is tied to special hardware.
Yes, so instead up upgrading your video card for optimum performance, you have to upgrade your entire computer as it only works with CPUs having a specific instruction set.
I think the agreement between DAZ3D and Nvidia is mutually beneficial as DAZ Studio gets access to a Physically Based Render for its content and Nvidia gets access to a large pool of users to work with their renderer. The benefit is great to customers as they get access to this renderer for free and as it's integrated into DS, it's much easier to work with and get desired results easier than the reality or Octane plugin.
Just a quick little input. Turned on the magic acceleration. And my render speed quickly accelerated to a much slower crawl, as I mentioned on Deviantart as well.
I've tried lotsa lights, infinite spheres, finite spheres, scene only... yeah. I'm thinking there are some of us who won't be able to speed up at this stage.
Yes, so instead up upgrading your video card for optimum performance, you have to upgrade your entire computer as it only works with CPUs having a specific instruction set.
I think the agreement between DAZ3D and Nvidia is mutually beneficial as DAZ Studio gets access to a Physically Based Render for its content and Nvidia gets access to a large pool of users to work with their renderer. The benefit is great to customers as they get access to this renderer for free and as it's integrated into DS, it's much easier to work with and get desired results easier than the reality or Octane plugin.
If you have any AVX compatible CPU which became standard on all Intel Sandybridge or AMD's Bulldozer (released Q1 2011 and Q3 2011 respectively) to the present Intel and AMD line-up you have the "upgrade your entire computer" already.
A similar argument could be made in order to upgrade your video card (or change from a brand new AMD/ATI card which is useless with Iray in GPU mode) you could also be looking at an upgrade you power supply as well.
Except for a few very rare exceptions, I don't really understand the angst over video card upgrades to use Iray to best effect. People have been upgrading computers and graphics cards for years in order to be able to play some game or other more effectively. I'm one that is CPU only and know how slow some renders can be with it. I also know how slow some UE2 renders could be with it so I'm not really freaked out by the times. They have been all in a days work for a long time now. Not that I am not looking forward to a computer upgrade in the not to distant future.
I have 3 video cards just lying around because I swap out the GPU more; have a few hard drives as well.
The future is GPU rendering, not CPU. And it's not just in the 3D graphics, Adobe premiere, Video Converting software, etc.
And as far as I'm concerned the winner is nVidia, AMD dropped the ball on this, they do not have a competing technology.
The only upgrades that i've done to my PC over the last couple of years have been to the GPU.
If you have the money you can buy 3 titan x for about $4000 and see a 60 times increase in render speeds. if it wasn't for GPU rendering this would not be possible. ( should say if it wasn't for Nvidia, this would not be possible)
3 years ago if I wanted to see an 60x increase in render speeds, I'd have to setup a render farm with 60 PC. that's an investment of about $120,000. This is in the league of dream works and disney.
for $4000 I can have the same computing power as the big boys.
Nick
As the original poster (sorry, been offline a couple of days) I've not been able to get a single render to complete. It has only passed 14 iterations once (I think it got to 41), and yesterday I left it rendering all day just in case waiting 5-6 hours was just being impatient - never progressed past 14% again. When it locks up, it does so completely, I cannot cancel the render, I have to shut down DAZ from task manager (and yes, I've waited hours to see if canceling just take a while to finish, it never finishes). The only thing I haven't tried is the "magic go faster" opti box. I'm checking that now and I will let you know if it magically fixes anything.
As for reasons why I can't I upgrade my video card - I'm poor. I use DAZ because it's free. I have two kids in college and very little money to spend even on content.
I know that's not a universal complaint, but it's a shame that DAZ didn't implement this feature in a way that works for those of us who love the fact that DAZ makes it possible for those of us with little money to do 3D art at all. I will most likely move back to 4.7 until things like Reality are available in 4.8 (Reality is the only "big" money I've put towards rendering and it's slow as hell, but at least it doesn't freeze up).
I'll let you know if I ever find a way to make it work, but at this point I'm pretty much giving up Iray as something that is unusable for me.
Ok - I got one to complete, and I've successfully rendered the model 3 times from different angles... I'm not sure if one or a combination of the following was the game changer, but here are my tips. Since I've not thoroughly and repeatedly QA'd everything I can only judge success by the fact that I've been able to do a complete render in a few (7ish) minutes, after having no success for the last 2-3 days :
1) Do NOT attempt to load a scene previously created in DAZ 4.7. I was never able to get a render from a previously created scene, even when I reduced the items in the scene to only the model with no hair. However, when I created the file in DAZ 4.8 and simply applied a shaping and materials preset from the model created in DAZ 4.7 I was able to complete the render. With just the model and no hair it completed in 7 minutes.
At the same time I'd also done the following:
- check the box labeled OptiX Prime Acceleration on the Advanced Page of the Render Settings tab. Everything in the successful render went incredibly fast (by my machine's standards). The successful iteration numbers I'd been able to reach previously took hours to clock, this time it took minutes.
- Reduced the number of items in the scene to almost nothing - model only, no hair. Obviously how many items can be ultimately included is going to require more testing.
You might also try NOT using the IRay Uberbase presets. In my failed attempts, the only renders that clocked any iterations were when I did NOT use the preset and just used base materials. In the successful render, it should be noted, I did use the IRay skin base but that was the only shader in the scene. As I re-add items to the scenes I will be testing the renders with and without the IRay presets. If I determine anything conclusive I'll let you know.
Changing the lighting to hdr and finite sphere vs. infinite sphere with a date and time, both rendered with roughly the same times, but the lighting was actually better, imho, with the infinite sphere and time of day.
Thanks
"and we already have Octane"
Yea, but Octane in DAZ is a bug fest, can not animate with current state and dev lags way behind its 3D app counterparts.
I love Octane but have grown to hate Poser, this for me is a opportunity to move to DAZ and use a solid render engine that seems to have a nice focus on it for DAZ at least.
I did try Reality, it is way to slow IMO Vs Octane and early test Vs iRay too.