PBR and Shader Quality: Iray vs Everything Else
Nyghtfall3D
Posts: 813
Before reading, keep in mind I know nothing about how to create complex shaders or what's involved in creating them. I know how to tweak various properties in the Surfaces tab, but I don't know the first thing about what's involved in making shaders look hyper-real.
That said, would someone kindly tell me what the developers behind engines like LuxRender, Cycles, and Octane are doing to make their shaders look more realistic than Iray? I don't know whether my point of view is entirely subjective, or if there's really something else going on under the hood, but ever since DAZ licensed Iray for us, I've yet to see a single product released with Iray shaders that look as physically real as nVidia would have us believe they should. The only difference I've seen between their 3DL counterparts is that they look like margianlly more realistic painterly-style shaders. It's especially noticeable with anything that isn't metal and I'm starting to wonder if I should consider an alternate rendering solution.
Am I blind and daft, or do my observations have merit?
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Comments
I don't agree with your assessment, but I'll point out that lighting is just as important in realistic images as shaders.
I figured as much... thank you. ;)
I'll agree with ChangelingChick. From a long time photographer's perspective, a huge number of artists here don't seem to "get" light's behavior and impact on colors and shapes.
However, I have a significantly different opinion regarding this statement: "The only difference I've seen between their 3DL counterparts is that they look like margianlly more realistic painterly-style shaders. It's especially noticeable with anything that isn't metal".
Personal perception and expectations play a big part in any sensed consideration, but I'm well on the other side of your point. Leather, tile, and glass shaders are three examples of realistic surfaces. I also wonder if you're not conflating the shader and the actual uv's / maps.
You're right, I forgot about those other types of surfaces. I've seen remarkably realistic examples of each. I was thinking more about fabric when I wrote that line.
Paolo Ciccone once created a Lux-compatible mat preset with Reality for the Austrani outfit for G3F and compared it to its Iray counterpart in his ad copy. Arguably, I think his preset does look more realistic, but is that because of the lighting and other settings used in his promo?
...Iray in Daz is sort of like 3DL in Daz, limited as to what it potentially can do. The Iray standalone offers more features and settings but at a price..
Same for the unlimited core standalone for 3DL, you have to dig deep to get all the bells and whistles.
Above said, recent developments by a several very dedicated artists here (Parris Kettu, and Wowie) have pushed the boundaries and opened more of what 3DL is capable of, particularly when using the progressive or scripted modes. What I have been seeing from this is pretty astounding, far better in quality than even UberEnvironment can produce.
When and if, someone can dive deeper into Iray to do the same remains to be seen.
Were Reality not as buggy after ver 4.x was released and not as glacially slow, its results were really good, provided you didn't use the speed boost.
I only used Reality as an example because Paolo's Austrani shaders directly related to the question I was trying to ask. I will never go back to CPU rendering, nor will I look for any other engines. I've grown too occustomed to Iray and, for the most part, really enjoy what it does for the price.
+1 for sure. I think knowledge is a big part of it. The Luxrender and Octane users seem to be more knowledgable and more curious about how things work, in my observation. On the other hand, when a newbie asks a technical question in the Daz forums, the overwhelming response is "Just fix it in postwork. It'll look better and you'll save time." Obviously not everyone is like that, but I do hear it alot.
I'm guessing that DS/Iray has a lot more users than the other modelers/engines, since it has the lowest barrier to entry and is the most inviting to newbies. So it stands to reason that there are lot of people doing eye candy renders (simple portraits/vignettes with tons of postwork(NotThatThere'sAnythingWrongWithThat)). If you could count the number of DS/Iray users really striving for photorealism, there might not even be as many as in the Luxrender or Octane camps.
Do we even have any other tutorials to create Iray shaders? The only one I've even heard of is the Esha one in the store. And it's never dropped below $20, so I guess not many people have tried it.
Anyway, I think the engines are all pretty equally capable. Each has some advantages and drawbacks, and some may definitely be faster, but they are all capable.
..I wouldn't diss CPU rendering quite yet.
First most major film studios still use it because they can throw a boatload of memory at the process instead of be constrained by limited GPU VRAM. Second, they can afford warehouse sized render farms with dedicated networked render boxes that have Dual HCC CPUs.so they're not waiting for a single machine to pump out a high quality image by itself. They also render in batch mode which saves on system resources.
Carrara's and Vue's render engines can also produce very lifelike results as well.
With what I mentioned above about 3DL, it is beginning to look more attractive. Just working with Parris' IBL Master I am able to render a scene at a pretty high quality level in a fraction of the time it took to render when optimised for Iray on the CPU. When I get everything up and working again, I will be testing the scene using Wowie's AweShader (provided the scene file was not corrupted or lost when the HDD it was on started to go bad).
Point taken, but I'm not a film studio. I'm a hobbiest with a 4-year old CPU.
3Delight Cloud
Render interactively and seamlessly — using thousands of cores. 3Delight Cloud is currently in private beta. It will be made available as a public beta in October 2018.
http://www.digitaleng.news/de/3delight-cloud-and-3delightnsi-debut-as-new-rendering-tools/
Pretty cool
...mine is 6 years old and I still can render a fairly complex scene in 3DL on the CPU in 10 - 15 min that would take two or morehours in Iray.
This took 13 min on an old 2.8 GHz i7 930.
..that would be nice.
Well IMHO shader/material system of dazstudio is bad and need complete rework. For this reason and others i export and render in other engine.
Accepting for the sake of argument that your initial statement is correct, some potential causes that come to mind are:
There's a difference between looking subjectively realistic and being realistic in an objective sense - a shader mimicing the way light is reflected, refracted, transmitted and so on exactly as a particular real surface would do is going to take a lot of highly technical measurement and mathematical jiggery-pokery. We are talking about the former, I suppose, in which case what looks 'real' to Abel may not look 'real' to Anna.
And some of us who do Iray shaders aren't aiming for realism. ;)
Personally, I think Iray is realistic enough and most of the work goes into setting up the lighting properly, which isn't a code thing but more composition and photography (basically). Learning to light scenes properly is a big process once you've gotten through composition and crafting and fiddling with clothes, etc. I'm still learning to light right.
It's simply astonishing how much of a difference lighting can make; I've spent a lot of effort on scenes only to render and go 'this looks like garbage.' And then I have to focus a lot on lighting and, a few passes later.. it looks magnitudes better.
Better tech might help and make a difference, but I think it can become a crutch and diversion from creating well lit, compositionally dynamic scenes.
There are many reasons why assets in the DAZ Store do not look as photo realistic as they could and should in 2018.
Agreed that there are still challenges for skin. But to be clear I am talking about environments and props in this post.
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MDL - the shader language
The Shader Language of Iray is the Material Definition Language MDL. In theory it would offer all features to make photo realistic images.
There is nothing wrong with this shader language. It could even be supported by other render engines like Octane.
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Shader Builder - Shader Mixer - Node Graph Editor
One limitation is that it is not user friendly to work in the current shader builder or shader mixer.
You can not adjust in real time all the existing materials in a scene in a node graph editor but need to rely on a time consuming import export process.
In addition there is still not a node graph editor for the whole scene.
After seven years of DAZ Studio I have not observed a significant update to that system.
As a result instead of everyone being able to experiment and build advanced shaders only a few published artists provide some solutions.
When you check the material settings of DAZ3D licensed products you may notice that many only use some very basic material settings while advanced options remain untouched.
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Low detail vs high detail geometry and maps
One other important factor is the ongoing insistance of some DAZ3D published artists of using normal or bump maps.
Experienced eyes and even casual viewers can spot that something is off with the lighting because those maps do not produce accurate physically shadows but some sort of simplification.
Artists that create images for achrchitecture or other projects that focus on photo realism use high resolution assets in combination with displacement maps.
Some say that Iray can not handle displacement that well as other render engines. This may be true in some cases but not in all.
Some published artists are used to their workflow of creating low detail assets and have not adjusted for GPU rendering.
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It could be possible to include both in most environment and prop products:
- a low detail version with bump and normal maps
- a high detail version with displacement maps or the original high resolution geometry.
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alternatively:
DAZ3D could focus on high resolution assets that allow photo realism.
Morph 3D could focus on low resolution game assets.
Trying to do both at the same time may result in no customer group being fully happy.
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Most Octane renders I've seen have looked better to me than Iray renders look in general. I don't mean they're more realistic, they're just different in a way I like, which is what matters to me. Even some Bryce renders look better to me than anything I've seen made with DS (more brilliant colors).
Actually I don't care much for realism, if it just looks like a photo I find it boring. I actually like that you can see it's a render, just like an oil painting that looked 100% realistic wouldn't make much sense to me. There are of course cases where realism is wanted, but not with the stuff I'm currently creating.
..I definitely agree about the Shader Mixer and Builder. I've found creating materials in Carrara to be much simpler and I get a a close to real time view of what it looks like. This is why I don't understand why Daz (which owns Carrara) didn't go with this structure for the Shader Mixer/Builder.
I bet they make appropriate use of bump maps too. Consider a brick wall: the bricks have a rough surface, the render does too. Nobody is going to try to model every single grain of sand in the mortar with actual geometry, it's an ideal job for a bump map. Actually, theyre pretty unlikely to model every brick either - easier to use a displacement map to give some actual geometry to the surface of the brickwork and the bump map for fine grained effects.
And I bet you that all those images people applaud for their realism in the Zbrush forum or in the galleries of other professional software are not using bump or normal maps for dominant objects clearly visible in the foreground.
Yes, agreed most people are not going to model grain of sand.
Some modeling applications like Zbrush feature tools to create "noise"
Other Some render engines feature shaders with procedural displacement.
It is a willing choice at that point to transfer those details to bump, normal or displacement maps.
DAZ 3d published artists who use those tools could create and include material presets for each map type.
Then the users could choose if they would want to save resources or aim for the most physically accurate material simulation their render engine can provide.
This is a great way to save system resources if that is the goal.
But if you want to create a physically correct simulation of a material then you might want to actually model the surface of the brickwork and use a displacement map for the fine grained effects.
It is s a matter of personal choice, taste and the goals that are supposed to be achieved that will make you choose one workflow or the other.
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The original poster asked
tldr version:
It is not the fault of Iray or the Shader language that people are not producing photo realistic assets or images.
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Published artists can create the products the way they want.
Artists can create the images the way they want.
Customers can deceide if they want to pay for licensed content that is looking stylized or photo realistic.
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Funny you mention... a lot of the normals that are used in products at Daz are created by modeling that stuff at higher resolution, then baking normals from that to use on lower res models so you get a higher res look on a low res model. So even if folks are using bumps to get detail, there's a good chance those were made through modelling geometry and not painted/generated as 2D images.
'Other' render engines?
Many of my Iray shaders have procedural displacement:
https://www.daz3d.com/oso-shader-pack-1-for-iray
https://www.daz3d.com/oso-fur-shaders-for-iray
https://www.daz3d.com/oso-master-shader1-for-iray
And 3DL has several procedural displacement shaders (like AoA grass/rock). Mind you, it can take a fair amount of work to get photorealism out of 3dl, but it's possible.
In case these were options some folks didn't realize.
I updated the last post and replaced the word "other" with "some" to make sure the intended meaning is more clear.
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tldr try v1002:
- > The options are there. It is a choice for everyone if they use them or not
But yes, people need to know about the options to actually have that choice.