Iray vs Reality - Speed vs Functionality
Nyghtfall3D
Posts: 813
While reading this, keep my system specs in mind: 3.5 GHz Core i7, 32 GB RAM, 6 GB Geforce GTX 780, Windows 7 Pro 64-bit
The attached image is the Reality version of my first Iray render, "Baroque Grandeur".
Three days ago, I learned that Iray's default settings include several stop conditions that keep it from rendering until the user stops the process. This is unusual for an unbiased renderer, and explains why Iray has a progress bar. All of the stop conditions can be increased and disabled, to emulate Lux's render process, so I did.
I also noticed a couple optimization settings were disabled by default, including Architectural and Caustic Sampler, so I enabled them as well. Then, I tried re-rendering a technical exercises I did with Iray, called Baby Steps. DS crashed, twice, about 8 minutes into the render, so I submitted a bug report with a copy of my scene file, and am awaiting their reply.
Meanwhile, I decided to re-load "Baroque Grandeur" and see what I could do with it in Reality. Unlike my out-of-box Iray version, nearly every surface in this modified Reality version was tweaked to some degree. The candle lights are 10W mesh lights, and a 100W Reality Mesh Light is filling in the foreground detail. I think the result is a great example of the need to understand how material shaders work to get the most out of unbiased renderers.
Shortly after starting the render process, I adjusted the ToneMap settings in Lux:
Film ISO: 2500
Shutter: 2
f-stop: 5.6
About 5 hours later, I was extremely grateful for Lux's in-process ToneMapping functionality when I started experimenting with Film Response presets. I chose Fujifilm Cine F-125. Though I have no idea what kind of photography it's used for, I love the effect it had on this render.
The out-of-box Iray version of this image took about 45 minutes to render. The modified Reality version took 21 hours.
I enjoy Iray's speed, but Reality has clearly reminded me that function is far more important, especially when backed by a well-written user guide and superior tech support. And being able to continue working on a scene while Lux renders in the background is icing on the cake.
I understand a new version of Reality is currently in beta, and is expected to increase render speeds by 10% over what's available now, depending on scene complexity. Personally, I'm looking forward to it.
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Comments
NVIDIA made a change which stopped the ability to fully change tone mapping, and a couple of other settings, during a render, it is being looked into. To work on a scene while getting a preview of your render, there is an Iray Viewport mode. Please adjust the settings to get the best results for your hardware.
That's unfortunate, but good to know.
I've posted the re-render of Baby Steps on my deviantART page. It looks a lot better than the original.
Interesting analysis you're doing there Nyghtfall. Reality certainly has an advantage as far as documentation & a very artist friendly yet powerful interface to export to Luxrender. I adore Iray but still support any good physically based solution that works with tools like DAZ Studio.
I do want to clarify one point you made regarding the "10% speedup" in the upcoming Reality 4.1 & Luxrender 1.5. It's not a 10% speed up but a 10x speed increase! This is on the CPU, without getting into the added boosts that OpenCL on a GPU card will bring. See this post straight from the Codefather's mouth hehe http://preta3d.com/sneak-peek/
When this happens Lux & Iray will be neck & neck in terms of speed & I'm looking forward to seeing that. No matter which render engine you're using, the right light & material settings are key to maximizing the speed of an image render.
That relies on Luxcore...which at this point is STILL highly experimental, so 'soon' is more like the DAZ implementation of it than the common, everyday idea.
What surprises me with that link (which I have seen before) is the image that rendered 10 times faster is far worse quality (much more noise), so it seems a strange way of demonstrating the 10x speed up.
...however that 10x speed increase will only work if you have a Sandy Bridge or newer i7 as it requires the AVX instruction set
Some of us have the first generation i7s and even core 2 quads which would necessitate building an entirely new system as Ivy Bridge (Sandy Bridge is now obsolete) and newer Intel CPUs require a different CPU socket (LGA 1155 or 2011) to take advantage of the speed boost..
With my old Nehalem Bloomfiled i7 ( LGA 1366 socket) render times with Iray (99.1% convergence) are much shorter time than Reality/Lux (have yet to produce an image in Lux without a lot of discernible noise even after 15 or more hours of rendering). In Iray, depending on the scene I can get results in under an hour to about 5 hrs for a fairly complex scene, and this is with 4 year old hardware.
Looking to double the memory to 24GB (a much smaller investment) to keep everything in physical memory and eliminate the issue of swapping (the latter which happened a lot with Reality4/Lux as I'd get both "High CPU" and "High Disk Usage" messages).
I just felt there were too many bugs at the release of Reality4 for Daz to continue with it and ended up uninstalling the plugin after the second patch kept messing up my render camera assignments. There was also the issue of having to jump through extra hoops to get surfaces in older scenes to appear in the R4 Materials tab and having reset all the materials each time a new patch was issued..
BTW, anyone need a pair of XFX ATI Radeon Double D HD7950s? (need to generate funds to get that Titan X :cheese: )
Interesting since he claims it will be anytime now. Some claim it's a ploy to not lose his clientele. Time will tell. I am starting to play with iray in the meantime. iray is limited compared to lux for sure. Why would nvidia remove flexible functions? & where is this iray preview window? Nightfall killer render
Hi Spooky
I still get all the in-render tone-mapping options, what is missing?
Interesting since he claims it will be anytime now. Some claim it's a ploy to not lose his clientele. Time will tell. I am starting to play with iray in the meantime. iray is limited compared to lux for sure. Why would nvidia remove flexible functions? & where is this iray preview window? Nightfall killer render
Click on the draw style next to the camera/view drop down list and select NVIDIA iRay. The preview is not instant, but particularly if you have an nVidia graphics card will give you a preview of the scene in a few seconds or so. I use that option in a smaller auxiliary viewport in a similar way to I use the IPR render mode in the auxiliary viewport when using 3Delight. It is a very good way of previewing you light and exposure settings.
Hi Spooky
I still get all the in-render tone-mapping options, what is missing?
They are not missing, it is just that in luxrender you have the option to manipulate these even when the render is running, which is not an option with iRay. However Spooky implies that this is due to a bug nVidia are aware of, and when this is fixed, maybe this will be possible as well. iRay is still very new and hopefully functionality will improve further over the coming months/years. We saw improvements even during the beta period, for example an ability has added to stop the render and later resume it.
Click on the draw style next to the camera/view drop down list and select NVIDIA iRay. The preview is not instant, but particularly if you have an nVidia graphics card will give you a preview of the scene in a few seconds or so. I use that option in a smaller auxiliary viewport in a similar way to I use the IPR render mode in the auxiliary viewport when using 3Delight. It is a very good way of previewing you light and exposure settings.+
Thanks since I have my AMD tower at home characters goes all white but will work on my nvidia laptop
Hi Spooky
I still get all the in-render tone-mapping options, what is missing?
You cant adjust it while rendering like one can with the luxrender
They work during a render for me!
I'm talking about that slide out menu in the render window
Interesting, which leaves me confused why Spooky made the comment.
Note that the preview mode should work in CPU mode on your AMD, but will be much slower.
Holy Rendering, Batman! I had NO IDEA you could do this! I never even noticed that little arrow on the side of the render window.
You just made my life 100x easier! Thank you!
Well, speed increase or not, coming from Reality 2, the Reality 4 interface was like a punch in the face followed by a kick to the gut. I'd rather go back to 3Delight than spend 5 million years setting up a scene for LuxRender using this atrocity. Especially since, last time it checked, it still didn't support combining bump and normal maps, also known as almost every single gen6 character.
The whole thing was sort of a big letdown.
Oh! Nice!
I use the Darkside window style, and the arrow appears as a dark grey rectangle, so it wasn't clearly visible until I moused over it.
Thanks for reminding me to have my husband check my computer specs. My machine is pre-Sandy Bridge, so I guess that answers that.
It's been a hard choice moving from Poser to D|S, but if the new release of Reality isn't going to be as effective for me, then that makes it less difficult to leave that workflow behind for the most part. I'm extremely impressed with the speeds I'm getting with Iray even with just CPU rendering.
(Lots of love to Paolo and his team, though! I've never seen better tech and community support for a product.)
Very cool thanks now I need to learn materials lighting ect as I had to with lux having said that I will be able to use it with my 2 machines. Meanwhile I have faster rendering options cool! If i do go Iray i would most likely swap out the AMD fire pro in my tower. From what i understand one does not have to spend over a grand for a decent card..
Another significant drawback I've noticed with Iray is that, when it starts rendering, my PC's overall performance nosedives. Not so with Lux.
Is there a way to limit the amount of GPU resources Iray uses, or do I need another video card?
There is that. The last test I tried with removing that silly time limit, a render that took 7 to 8 hours with lux would of taken prolly 2 to 3 with iray using my AMD machine.. I really do hope faster lux is coming because it is still a more flexible render engine, and more tools one has to play with the better.. At times I like to layer render and blend them this could be fun for that..
I have to set Studio to lowest priority in Task Manager or it'll completely take over my computer and I can't even browse the internet.
Cool beans does it slow rendering down?
Huh?
That's the whole purpose of Iray (and any other GPU accelerated render)...maximum use of GPU to minimize render time. It's best to NOT do anything else when rendering...or get a second (can be much lower spec) video card to handle OS/screen duties...a $30 1 GB GT400 series card would work perfectly for that, if you must do other things while rendering.
Iray is very powerful (and power hungry) software that is designed to run full throttle...and use everything it can get and still want more, with one goal...minimize render time. Lux USED to do that to. But, unfortunately Luxrender has (since some of the later 1.3/1.4 betas) been 'throttling' or adjusting it's behavior to 'play nice' and NOT run full throttle...imagine what it could do if it was allowed to run full speed.
The whole 'my computer's running at 100% CPU/GPU when rendering, I need to do something about it' thing, to me is like...yeah, that's what it is SUPPOSED to do. You don't run the Indy500 with an 8 cylinder engine that has 4 of those cylinders disabled and expect to get to the finish line in a reasonable amount of time.
Nope. I just ran SickleYield's benchmark test, and it still took just 3 min 40 sec to process 5,000 iterations and reach 89% convergence with CPU + GPU rendering after setting DS to Low Priority.
I understand the purpose of using Iray, and want the get the most out of it that I can, but I spend most of my free time in front of my computer. If a render engine is going to use so much processing power as to limit even the most basic of functions - Windows Explorer, surfing the net, watching videos, etc. - while rendering, it's of no use to me.
I am not sure about the doing nothing else when rendering, some of us use our main machine to work with, and for web browsing, so it is very nice to be able to do things whilst the render is running, particularly a long render.
There is a number of options you can do to achieve this:
1) For 3Delight and iRay CPU only, open up task manager, find the DAZ Studio process, then right click to get the popup menu and select "Set Affinity". Unclick some of the CPU's (they are actually hyperthreads rather than CPUs), you would have to have a very old processor if only 1 CPU is present. Generally 1 or 2 free CPU's are enough to allow for web browsing etc.
2) For iRay GPU then simply unselect the CPU. If you have a decent GPU the CPU will only reduce the rendering time slightly, and if unselected allows you to continue to work on your PC more or less as normal.
Nightfall & I are spoiled by using luxrender. I have to learn everything for iray so far I just ran "out of the box" to see how well it would work with multi character scenes it does... I guess to be expected when you work with something for 3 years...
EDIT is it possible to set up both types of cards on 1 machine with software that would assign a program to a specific card?
They are not missing, it is just that in luxrender you have the option to manipulate these even when the render is running, which is not an option with iRay. However Spooky implies that this is due to a bug nVidia are aware of, and when this is fixed, maybe this will be possible as well. iRay is still very new and hopefully functionality will improve further over the coming months/years. We saw improvements even during the beta period, for example an ability has added to stop the render and later resume it.
...it would really be nice if you could stop and save the render to resume at a later time like Lux allows. Of course that would require a means to render in background independent of the main application.
...that's why I use my old notebook for online stuff. I want Daz to have the highest priority on the workstation as that is what it (the system) was built for.
They are not missing, it is just that in luxrender you have the option to manipulate these even when the render is running, which is not an option with iRay. However Spooky implies that this is due to a bug nVidia are aware of, and when this is fixed, maybe this will be possible as well. iRay is still very new and hopefully functionality will improve further over the coming months/years. We saw improvements even during the beta period, for example an ability has added to stop the render and later resume it.
...it would really be nice if you could stop and save the render to resume at a later time like Lux allows. Of course that would require a means to render in background independent of the main application.
Thats not as much of a deal breaker due to not needing as long to render same with not having a refine brush.Due to being used to luxrendering i can let it run until the noise that drives me nuts is all gone. That is not always the case with lux sometimes I need to PS noise out..+