General GPU/testing discussion from benchmark thread
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Considering that all the renders I've post-denoised with the standalone Nvidia denoiser have only taken a few seconds (on a GTX 1070) I hardly see the point. If the DS version slows thing down considerably I'd say post-denoising would be to prefer. That can be done in DS also AFAIK.
I have noticed that if I crash during rendering in the view, it's almost always because I have the denoiser enabled (RTX 2070). It almost never crashes with it disabled. Not that it crashes often with it enabled of course. Just sometimes.
FWIW, Iray is absolutely a "real time renderer". However the term "real time" is so vague as to be meaningless. All renders take time, and "real time" doesn't answer "how long?".
Iray is also based on ray tracing. It's preview has two built-in main modes, "Photoreal" and "Interactive". The main difference being the amount of shortcuts taken to derive the preview image, and therefore how fast the image is derived. However, the main factor in how fast any renderer generates an image is the hardware and software capabilities and settings.
We can all make a simple scene, and using Iray Photoreal generate a very fast ("realtime") raytraced image. With a more complex scene it requires more calculated ray bounces (among other things), which can take more time, depending on the hardware and software implementation.
So it all comes down to hardware/software implementation, and how many shortcuts you're willing to take. Video games generally take more shortcuts so they can have decent framerates. Iray can also take a bunch of shortcuts depending on how you set the Draw Settings. Or it can be very accurate.
However, with the new RTX "realtime" raytracing (and related hardware/software technologies) fewer shortcuts need to be taken. Raytraced reflections can now be done in games where they might have been prohibitively slow in the past. Also, new denoising features improve the apparent image quality and rendering speed. Presumably, since Iray is also a raytracing engine and will support RTX technologies, it also should take advantage of the "realtime" ray tracing and related RTX technologies.
So the question becomes, "assuming Iray will support and implement the RTX technologies to speed up its natural ray tracing engine, as well as utilize the RTX denoising and other features to improve its preview mode, how much faster will the existing Iray Photoreal preview mode be?".
Yeah sure, a slow car is also a fast car if you are of the opinion that "fast" is a term so vague as to be meaningless. With that argument I can explain away just about anything.
Fact is, real time is not a vague term in rendering whatsoever. Real time means that a finnished frame can be displayed at least 30 times per second on the target hardware, more likely 60+ on PC. Real time raytracing or not, that is the definition of real time and Iray does not fit that defintion whatsoever. Iray is an unbiased renderer which is just about the polar opposite of a real time renderer, which by its very nature is the most biased renderer out there. So biased that it uses a completely different process to calculate a frame called rasterization, and any real time ray tracing is going to be implemented on top of those rasterization techniques.
I'll keep in mind that Iray is real time next time I wait 30 minutes for one image to render even on the fastest currently available GPU
It's not meaningless in my business (software engineering). It means "a time constraint". If you think your render is an acceptable standard in about 20 minutes, 20 minutes is your real-time constraint. You can set that of course. What most people usually mean by "real time" though, is rendering a frame within such time constraint as your eye is fooled into perceiving continuous motion. For most games that's a minimum of 60 frames per second (16.6666r). For animation it's as low as 24/48, though in my experience animations at 60 fps look a lot nicer. It's just very hard to render anything more than a few seconds for anyone without a huge GPU farm.
Yeah I forgot you could go for real time movies, in that case I guess that would have to render at 24 fps. Maybe if you wanted some kind of Wallace and Gromit stop motion look, you could get away with 15 fps or so. Let's say we bend that real time term to the max and define it as "at least several finished frames per second".
Of course we can always split hairs. Is an unoptimized overloaded game that only runs at 0.5 fps not real time anymore? Obviously it's stil a real time renderer, but just so overloaded that it cannot possibly be considered real time in terms of the experience you get. Likewise, if you have the simplest Iray scene that renders in 0.5 seconds, does that mean Iray is now real time? Of course not.
The discussion was around whether Iray preview would benefit, and how much, from RTX. Nothing to do with video games. We're talking about DAZ Studio, Iray, and Iray preview, and how the new RTX technologies affect those things. Nobody here needs a frame to render in 1/30 of a second, although Iray is certainly capable with the right scene, settings, hardware and shortcuts.
What's important here is fast feedback in an Iray preview that can get very slow. And presumably that will improve with RTX. The question is "how much?".
Real time is not remotely vague. While it can vary some, real time refers to having the render drawn at a speed that appears to take place instantly to the viewer, thus real time. Video games are most often associated with real time rendering, because they render images at a rapid speed to create in motion. 30 frames per second is a baseline, but humans perceive motion at lower rates. Movies are often still at 24 fps, which has been a standard since 1920s.
30 fps means the image must be drawn in 33 milliseconds. Don't blink, LOL. That is how fast video games render their frames, and as I said that is a baseline. Most players very much prefer 60 fps, which is 16 milliseconds. There are high refresh rate monitors that go to 144 Hz, and beyond. To draw frames at 144 Hz, that means drawing frames in less than 6.9 milliseconds. I'd like to see Iray top that, LOL.
Video games that have enabled RTX ray tracing take massive performance hits. While this gets on gamer's nerves, the games still can render frames in real time with RTX.
I think Daz may get some kind of real time rendering mode. I do not think it will be Iray, at least it wont run like Iray does, just like Iray Preview is OpenGL and not using the same API. I don't think RTX will even be required to use it, since Pascal can cast rays, just much slower.
Have you tried the denoiser in the newest beta? According to release notes the updated denoiser looks visually different. So you may see different results from before. This is something I am most curious about, as it does not say how it looks different, just that it is.
Sorry but currently the discussion was around this false statement. And that has everything to do with video games, because they are the target of real time raytracing, and the rendering in game engines is what is commonly referred to as real time rendering. What happens in Iray is not.
Okay, so I guess the consensus is that RTX won't improve Iray preview. That's all I needed to know. Thanks.
Oh I think it will improve Iray Preview, just as much as Iray in general. Both will be faster, how much we will have to see. Just forget about "real time" in this context
I would say it's a game that's violating its real-time constraint.
BTW, as Iray Preview uses OpenGL, it may be worth pointing out that many video games are indeed based on OpenGL. So...yeah, it is valid to mention gaming in this discussion of real time rendering. Any real time mode that Daz Studio makes use of will basically be a video game engine. Not to mention that Unreal and Unity both have real time ray tracing now, so more video games can use this feature. People can also use Unreal and Unity to create animation. There are a variety animations that use these game engines already, and that list will grow now that they have ray tracing.
As to why RTX may not enhance Iray Preview, well, that is a different API. You would need to update this API separately to take advantage of RT cores and/or Tensor cores. Iray Preview is not at all like Iray Photoreal, they only share a name. As I already said, Iray Preview is more like a gaming engine, Iray Photoreal is the ray tracer with all the bells on.
Yeah, and I'm so sorry to say I just can't get anything good out of it. I don't know, maybe I'm doing something wrong but then again there's not very much to mess up. What shocks me the most is that I can have it kick in at low iteration, or even damn near the render is already finished and both times it just blurs out everything. I just have no clue what is supposed to be AI or intelligent about it. It cannot even retain eyelashes. It frankly doesn't seem to analyze anything, it just slaps a sloppy noise reduction post effect over everything and I don't get what exactly the AI has been learning so far. Maybe it has been busy coming up with a plan to remove the human race from this planet instead. An endevaour not without some merit, I'm sure. Or maybe it really just isn't meant for rendering characters, which would make it kind of pointless in Daz Studio?
I thought AI denoising meant that the scene is actually analysed. All the information is there. What is texture, what is geo, and what is noise that doesn't belong in there?
Well, the way the AI denoiser supposedly works is that it was "trained by AI" algorithms. Basically is was fed a bunch of pictures by machines, because people are not fast enough. So in order for the denoiser to work well, it needs to have experience with images in question. Non organic things are pretty common. Wall paper, wood, the corners on the floor. ect, all these things are common enough that the denoiser can possibly guess what pixels are missing.
However, people are different. People vary wildly. And while an AI might be able to create believable looking fake humans from photographs (this is a thing), it probably does not know what your specific characters looks like. Thus the blur. Perhaps if it was somehow possible to train the denoiser on your specific characters by feeding it a bunch of pics from different angles, then it would be better at denoising those images.
That's just my thoughts on it. When I use the denoiser for rooms or environments, it works like a champ. Sometimes it is ok with people, but it depends a lot on the character.
Supposedly with more training the denoiser will get better with time. But it has to be updated, so we have to watch change logs to see if any changes are made.
I don't want to further derail the discussion, but some clarifications:
I believe Studio now offers only the Iray "Photoreal" and "Interactive" as the primary modes (as well as some "Blend" modes), and I think "Iray Preview" is just a general term for the UI display for these modes. And I believe the OpenGL mode (aka, Iray "Realtime" mode) isn't an option with Studio, and perhaps was an older/deprecated mode (not sure about that). I believe that Iray has its own internal API's, together with CUDA, for both Photoreal and Interactive mode rendering, and doesn't use OpenGL. In fact there's no mention of OpenGL in the Iray documentation.
So the assumption is, IMO, that if Iray will support RTX, then its internal API's and libraries like the neuray DLL will also be updated to utilize some or all of that architecture, and therefore some or all of the present Iray functionality will utilize RTX. Possibly a bad assumption, but at least reasonable, IMO.
I don't think that's true at all. If it were, then ebergerly would be indeed right to hope that Iray Preview could get much faster with RTX. Iray Preview to me is exactly the same as Iray proper, only that it renders progressively while you can still work on the scene, and it has some limitations. Or actually just one, no displacement? Is there anything else?
Iray Preview has nothing to do with game engine rendering. this is not real time in any way. It uses the same general procedure to render as the normal Iray and the same API. Anything else wouldn't make any sense whatsoever. It needs to look and act exactly like Iray or else it would not fulfill its purpose as a preview for Iray. I have never noticed anything looking different in a full render than what I saw in the preview other than dispacement. Malicious tongues might say that displacement doesn't work in Iray period
BTW, here's a description of the "Interactive" mode:
So I think it's reasonable to assume that the faster "Interactive" mode is some shortcuts taken on the slower and more realistic "Photoreal" mode.
By the way. The plain OpenGL viewport, without Iray rendering, that is essentially a really rudimentary real time renderer. If you poured enough resources into that, you could make it look way better and essentially have a little mini game engine just like Evee. That is not feasible though, you'd much sooner just integrate another third party solution.
Iray Interactive is NOT the Iray Preview.
"Iray Realtime is an OpenGL render mode which uses conventional GPU raster algorithms to achieve realtime rendering speed. Iray Realtime targets a look for the materials that is closely matching the look in the other render modes. However, it has limitations when it comes to accurate reflections and refractions as well as lighting simulations. Iray Realtime leverages OpenGL 3.3 and NVIDIA extensions. It is ideal where rendering speed or large display support has priority and limited photorealism is acceptable."
This is why Iray Preview looks so different, folks. The language is important here, because "conventional GPU raster" is what video games use to render. Iray Realtime...which is used for Iray Preview, is basically a game engine.
It has nothing to do with RTX at this time. It has to be updated for RTX just like Iray itself does. That has not happened yet. Yes, RTX drivers that add ray tracing to OpenGL exist, but just like the Iray SDK, it is up to Daz Studio to update to use OpenGL with ray tracing. Who knows, this might be what Daz Steve was refering to when he said Daz would get RTX support. Recall he never specifically said Iray, so we don't know. But I personally think it is both. We will get a real time ray tracer and get an updated Iray with full RTX support.
No way.
I am very much assuming that is all true for Daz Studio as well. Otherwise we wouldn't even need this plain OpenGL viewport that we currently have at all.
Yeah I mean, just from a common sense point of view, think about it in the context of what you said above. Real time, 30 fps. Does Iray Preview feel like that to you? No, it feels like the usual progressive refinement that Iray proper does, including the loading delays and stuff going gray when you change something. The log is pretty clear too when you start Iray Preview.
And then it starts counting up the iterations just like a normal render.
I have also never noticed a visual difference in Iray proper vs Iray Preview and I render a lot. Such a thing would drive me absolutely insane.Alright, perhaps you are correct. But it is weird how things are set up, because messing with Iray Interactive settings seems to do pretty much nothing for me.
But I see all sorts of differences between the preview and final render. Some characters look downright purple or some other color in Iray preview. It does not work well at all for making such adjustments to skin. Even the lights look different in preview to me, some lights don't show up properly, or are much stronger in the preview than they actually are in the final render. Its good for catching things like bad poses or clipping, but that's about it.
When I use the preview, I get anywhere from 5 to 15 frames per second reported by MSI Afterburner. My help log reports it is running at 3-5 frames per second. All things considered, that is still pretty fast! The initial load takes time, but that is also true of video games. You have to load the scene before the render starts, even for games, so even if Daz gets a really fast real time mode, we still have to deal with some kind of loading time as the scene loads into GPU VRAM. I do not see any way around that, and I think this is probably what bothers you most about this mode. Once you get past that initial load, you are playing pretty close to real time. Move the camera and the picture quickly adjusts. Loading the scene into Daz Studio does not mean everything loads into the GPU. You have to wait for that process whether you use the preview or do a full render.
All it needs is more options, and an option to render to a window, which would allow people to save these renders. So if RT cores can increase the frame rate by about 3 times or so, if everything stays the same, Afterburner might report 45 frames per second, and the help log may report 15. 15 is pretty darn ok for this purpose.
But just know that the scene would still need to load to the VRAM. Maybe improvements could be made in how Daz calls for data and loads it, but I don't know.
That's another issue isn't it. I'm sure the opportunity cost for Daz of upgrading or replacing the view renderer would be prohibitive, but real-time rasterised graphics has come a long way, when you look at what you can do in Unreal Engine, CryEng and even Unity. There's also the new low driver overhead interfaces like DX12 and Vulkan to consider.
Personally, I'm quite disappointed to learn that we won't be able to play video games in DAZ Studio with RTX technology.To me, that's a bit of a game changer (in a negative way).
Also, I'm unable to find "Iray Realtime" mode in the Draw Settings. Like I said, I'm not sure that the Studio implementation of Iray uses that mode, if that mode still exists. Perhaps there's a 3rd party Iray plugin (Iray+ from Lightwork Design) that includes it for those applications that use that plugin?
In any case, I think it's a bit irrelevant to the discussion of whether the "Iray Photoreal" mode in DAZ Studio will benefit from RTX. Again, since it is an integral Iray mode according to the API documentation, I'm not sure why there's an assumption that it won't be affected by the RTX technology.
So while we can speculate, I'd suggest we wait until we have actual test data to see how Iray in Studio ultimately improves regarding the "Photoreal" or "Interactive" modes, or even whether new modes might be introduced with RTX.
BTW, if anyone has any actual test data showing the state of "Iray Photoreal" response as new RTX-related features get implemented it would be great if they could get posted here. I'm thinking if someone can make some quick GIF's of before vs. after, showing the UI response, that would be wonderful, and would help guide us back to facts rather than baseless speculation. There's some nice, free screen-to-GIF screen capture software out there that make it real quick and easy. I'm thinking that a picture is worth a thousand words (or renders).
I'm thinking if we can do something like this it would be very beneficial to get a feel for how much faster RTX might be compared to pre-RTX:
DS supports/uses only Photoreal and Interactive modes in Iray, it does not - after evaluation by the Daz developers - use Realtime. If/when Iray supports RTX it will presumably have an effect on the Photoreal mode, and might have an effect on Interactive, but we don't know how great that effect will be (and I'm sure it will vary by scene content).
This sounds like nothing I have ever experienced. Can you make some screenshots?
I think what you're seeing here is the OpenGL performance of the viewport while Iray is running in it. I don't think this says anything useful about Iray. It is simply the OpenGL viewport doing its best to not delay too much due to Iray loading and unloading. Technically I think every little thing you do unloads and then loads Iray interactively. Change a morph dial? Unload Iray, update scene, load Iray. Move an object? Unload Iray, wait until movement stops, load Iray. This is different to a real time viewport where you can move stuff around in real time with no delay. Not sure about other stuff like morph dials, I think that would probably work in real time too though. Loading new stuff would have some delay, naturally.
One could try Evee to see to see how an actual real time viewport behaves I guess.
You hit the nail when you mentioned displacement between Preview and Proper (the HD Morphs are the best way to test this, as even a figure that has been subdivided 2-4 times doesn't look quite the same in the final render ~ some of the detail is lost).
HD morphs may look different in Iray Preview only because on the figure there may be different settings for "SubDivision Level" and "Render SubD Level (Minimum)". The former is used when rendering in Iray Preview, the latter in Iray Proper. Set them both to the same number (at the cost of viewport performance since it will have to push more polygons) and you should see no difference.