Iray Versus Octane Renderer in Daz

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  • kyoto kidkyoto kid Posts: 30,604

    ..I understand , waiting patiently.

    I could never seem to get skin looking right in Daz3D's version of Iray even with merchant resource content.  Characters always seemed to look like dolls made of silicone or rubber (in some ways, the Gen4 skins looked more "real" in 3DL)

    I spent a fair amount of time on the Iray Skin thread. but then it became way too technical (talking about the actual real world physics,instead of discussing different parameter settings) and went right over the head so I left.

  • Rashad Bryce-CarraraRashad Bryce-Carrara Posts: 1,699
    edited December 2018
    joseft said:
    kyoto kid said:

    ...well again for people like myself the subscription track is a welcome addition particularly given what Octane is capable of. 20$ a month to get our of core rendering is a big incentive as suddenly even with a 4 GB GPU the process doesn't dump entirely to the CPU as it does with Iray once all the VRAM is filled. 

    On another note, am hoping to see more side by side render comparisons (along with process benchmarks) between Iray and Octane in Daz 3D. Particularly interested in seeing teh differences in how skin and hair are handled.  My system is still down as I am doing a full rebuild with some additional updating after the HDD crash..

     

    IMO Octane is overall a much better engine than iRay. However, mainly due to the shader/material structure in Octane, getting good/realistic results for skin can be much more difficult than it is in iRay and other renderers. In particular, getting the layered/translucent effect of skin is probably the hardest part. Octane is certainly capable of doing it, but to achieve it generally requires a very complicated material setup with multiple nested material mixes and your node editor looks like a big jumbled mess of connections. 

    I dont have any side by side comparisons at the moment because i am at work, but what you will see from both engines will certainly be comparable, its just the effort and experience required to get that result that is vastly different.

    Joseft,

    Funny, I was thinking the exact opposite in terms of realistic skin shading.

    Much of this comes down to how we define realism. To me, a surface is only realistic if I feel as if I could literally reach into the screen and touch these surfaces with my bare hands. If a surface glows then to me it will almost always appear as if it is out of thermodynamic equilibrium and therefore probably NOT comfortable to touch with my bare hands. The skin can have all the pores and wrinkles and other imperfections in place but if the nose glows too much then my belief will not be suspended.

    To my tastes most of the Iray renders I see show an SSS that shines directly through the skin. Fingers glowing and noses glowing as if these were made of air on the inside. Perhaps this is due to incorrect refraction settings, or maybe not enough attention being paid to light being absorbed, perhaps too much focus on getting redness that they are sacrificng any sense of depth or "weight."

    Octane by comparison, can give you the SSS effects needed while still managing to absorb light. Things dont glow that shouldnt glow. I can apply settings that can at one time get light shining through the back of the ears and the very tips of the fingers while still occluding light in the rest of the fingers as well as thicker areas such as the neck and torso and arms. All in the settings, no SSS strength maps required.

    It should be stated, that Octane has two different Transmission Tools. The Transmission offered in the Diffuse Material is a lot like the one we see in the Iray renders. It tends to behave more like a translucency, very good for  leaves and other thin objects that correctly tend to allow most of the incoming light to pass through them. However, the Transmission that comes with the Specular node works very differently, handles refraction within the medium much much better, and is the without question the best way to make skin. This is the reason why most skins are built omn the Specular material, well that and the fact that the Specular Material gives you an automatic "Top Coat" offered as the basic Reflection. Anyhow more on that some other time.

    I personally do not have enough mastery of Iray to determine how much of this common rendering shortfall of lacking refractive depth is user preset related and how much of it is limitation of the software. My general impression is that the current presets we are using with Iray are not absorbing enough light, allowing too much light to traverse the interior, making entire fingers and hands to glow. The best thing for Iray is for there to be some sort of conversion script so that user like myself can easily reproduce the effects we're getting in Octane in Iray. I'm sure Iray can do it, but I dont think very many of us are getting there just yet.

    Quickly here I have included a test render I made earlier today with Octane. The purpose of this test was to see if i could overcome the limitations of the resolution of the texture maps, by carefully mixing in a random noise element both in the albedo and in the normal mapping parameters. I think the test is successful.

    While we are here I can also point to the way the SSS operates and why it looks better to me than most of what I am seeing with Iray. Several things I like about this particular skin rendering

    1. Specular reflections are being "broken up" by the real details in the normal texture maps

    2. This is actually a texture for a younger person. I wanted to add age details geometrically because I wanted to see the way the SSS would behave in protruding areas such as under the eyes. I've seen several old people in real life with these sort of bags under the eyes, and the softness of the flesh in that area. I feel as if I've captured that here in Octane, without resorting to a depth setting so low that light shines all the way through the medium.

    3. The SSS effects remain subtle. When you look at the ears, you can get a real feeling of fleshiness, which to my mind is more important than focusing on achieving a bright and obvious red glow as I've said I think we focus on too much here. We shouldnt see a glow unless there is a very very strong backlight. Notice how the nostrils again show a softness, but the skin itself doesnt appear to be hollow. Softness without going to a hollow place...that is the proper ideal. It would be easier to demosntrate this as a side by side but alas I'd never point to another person's work and compare my own with any intent to indiciate that my own recipe was in some way better.

     

    Example 6.jpg
    1264 x 1000 - 1M
    Post edited by Rashad Bryce-Carrara on
  • RobotHeadArtRobotHeadArt Posts: 704
    edited December 2018

    When comparing render engines it's helpful to understand the design goals of the engine creators.  If you look at the official Iray plugin site, you will see how they are marketing the Iray render engine to a very specific market.  Architecture and product visualization.  It is not designed to be a character or VFX render engine.
    https://www.irayplugins.com/iray-for-maya/gallery.php
    https://www.irayplugins.com/iray-for-rhino/gallery.php
    https://www.irayplugins.com/iray-for-3ds-max/gallery.php

    Notice how those galleries are totally unlike the Daz gallery :D

    You can also tell how low character rendering is on Iray's priority list in that there are no built in native hair shading primitives and no 3rd party hair plugin supports Iray (whereas many of them do support Octane and Redshift).

    Iray is also designed for ease of use.  That's why all of the sampling parameters are abstracted away and you cannot set samples on lights independently of each other or override shadow behavior.  The creators describe the design decisions of Iray in this whitepaper "The Iray Light Transport Simulation and Rendering System" https://arxiv.org/pdf/1705.01263.pdf 

    A soup spoon and a tea spoon might look similar and you can substitute one for the other but each has a function that it is better suited for.

    Post edited by RobotHeadArt on
  • kyoto kidkyoto kid Posts: 30,604
    edited December 2018

    ...good point.

    I have always felt from the beginning, Iray (even Daz3D's version) really worked best with objects like tech, vehicles, furnishings, and architecture, along with smooth hard surfaces like polished stone, metal, plastics and glass.  When it came to softer and more organic materials like cloth, plants, hair/fur, and particularly skin, it seemed to be somewhat lacking. 

    So essentially, in Iray, we have a render engine that actually isn't well suited to the primary focus of the Daz software, characters.

    ...to quote Mr. Spock , "fascinating".

    This information is actually a big help 

    Post edited by kyoto kid on
  • If you look at the official Iray plugin site, you will see how they are marketing the Iray render engine to a very specific market.  Architecture and product visualization.  It is not designed to be a character or VFX render engine.
    https://www.irayplugins.com/iray-for-maya/gallery.php
    https://www.irayplugins.com/iray-for-rhino/gallery.php
    https://www.irayplugins.com/iray-for-3ds-max/gallery.php

    Notice how those galleries are totally unlike the Daz gallery :D

    My observations of Iray renders created with DS completely echo kyoto kid's.  Since DS 4.8 was released, I've wondered why characters have never looked remotely realistic as inatimate objects.  This... explains... everything...

    Thank you.

  • kyoto kidkyoto kid Posts: 30,604

    ...odd, that in playing around with the new advanced shaders and lighting for 3DL (just before I had the HDD meltodwn), I felt skin and hair actually look better than in Iray. 

  • nicsttnicstt Posts: 8,334
    kyoto kid said:

    ...odd, that in playing around with the new advanced shaders and lighting for 3DL (just before I had the HDD meltodwn), I felt skin and hair actually look better than in Iray. 

    Then they did.

    I don't like to term real/realistic; I prefer believeable.

    Does the render sell itself to me. I prefer much less shine than seems the norm so that is one of the first things that kills it.

    But other aspects like hair poses; loose stray hairs and matching hair colours (obviously artificial hair colour isn't an issue.). Painted on eyebrows can look really good, but not side on.

    Clothes draping (dforce is a big plus here TY Daz and VWD). But cloth thickness too can easily be an issue.

    One thing I've learnt (many others have said similar or related), is that if one doesn't like the scene, change the lighting - either the position, strength, or types; or combinations.

  • MattymanxMattymanx Posts: 6,000
     

    Submitted Questions in ticket: #287473

     

    Linvanchene,

    My appoligies for my original comment.  I was not at all clear nor correct in anyway and it was meant only as an assumption and not as fact.  I am sorry for any misleadings.

  • kyoto kidkyoto kid Posts: 30,604
    nicstt said:
    kyoto kid said:

    ...odd, that in playing around with the new advanced shaders and lighting for 3DL (just before I had the HDD meltodwn), I felt skin and hair actually look better than in Iray. 

    Then they did.

    I don't like to term real/realistic; I prefer believeable.

    Does the render sell itself to me. I prefer much less shine than seems the norm so that is one of the first things that kills it.

    But other aspects like hair poses; loose stray hairs and matching hair colours (obviously artificial hair colour isn't an issue.). Painted on eyebrows can look really good, but not side on.

    Clothes draping (dforce is a big plus here TY Daz and VWD). But cloth thickness too can easily be an issue.

    One thing I've learnt (many others have said similar or related), is that if one doesn't like the scene, change the lighting - either the position, strength, or types; or combinations.

    ...indeed, lighting can either be a big secne maker or a scene breaker. 

    Matching hair and eyebrow colour is a constant issue. I often use Skin Builder Pro (both versions)  so I can tailor the brows to match the hair colour.  I also have a fibremesh brow utility however unless one is doing portraits or close ups, "painted" brows work fine.  

  • Well, OTOY representatives spill some beans by saying that free tier is mainly intended for those ecosystems, where the main software is free to use, like Blender, and Unity.... Guess Daz fells under this category quite nicely, no ?:)))))

    I tried the Octane 3 demo plugin earlier this year,  and it feels much more ambitious than Iray. It also advances much much faster,  with new features being added constantly, engine optimized etc.

  • jaxprogjaxprog Posts: 285

    Over the years, I've been tempted to get octane. Alot of renders look realistic. However for me, the models in octane look hyper-realistic to the point where it looks fake. That's the one thing, that's held me back. I used to use Reality, but as soon as Daz came out with iRay, I shelved Reality. Don't use it anymore.

  • kyoto kidkyoto kid Posts: 30,604

    ...yeah Reality still uses LuxRender 1.6 which has been abandoned by Lux development.  As I mentioned earlier, they have new engine out called LuxCore, however so far only has plugins for a couple of the big name softwares.  Went to the Reality forums and a in post made back last spring/early summer, Paolo mentioned about upgrading the plugin to LuxCore which was supposed to be ready be the "end of this year" (where we are now), but so far, seen nothing.

    Sad it had promise and was the first photoreal render engine made available to us. I liked the different film filters, materials setup, and ability to render outside the Daz programme (which saved valuable system memory), just not the rendering time that seemed to be on a geologic scale.  Realti4.x was also unstable compared to 2.5 and every time a patch was issued for one bug, something else broke.  I ended up shelving it as well. 

    When I get my main system up and running again I'll be getting the Daz Octane subscription.

  • wolf359wolf359 Posts: 2,343
    edited December 2018

    When comparing render engines it's helpful to understand the design goals of the engine creators.  If you look at the official Iray plugin site, you will see how they are marketing the Iray render engine to a very specific market.  Architecture and product visualization.  It is not designed to be a character or VFX render engine.
    https://www.irayplugins.com/iray-for-maya/gallery.php
    https://www.irayplugins.com/iray-for-rhino/gallery.php
    https://www.irayplugins.com/iray-for-3ds-max/gallery.php

    Notice how those galleries are totally unlike the Daz gallery :D

    You can also tell how low character rendering is on Iray's priority list in 
    that there are no built in native hair shading primitives and no 3rd party hair
     plugin supports Iray (whereas many of them do support Octane and Redshift).

    Iray is also designed for ease of use.  That's why all of the sampling parameters
    are abstracted away and you cannot set samples on lights independently of each
     other or override shadow behavior.  The creators describe the design decisions of 
    Iray in this whitepaper "The Iray Light Transport Simulation and Rendering System"
     https://arxiv.org/pdf/1705.01263.pdf ;

    A soup spoon and a tea spoon might look similar and you can substitute one 
    for the other but each has a function that it is better suited for.

     

    Thank you for this post.
    It is worth mentioning that NVDIA is primarily
    a hardware manufacturer and IRay is their "Loss leader" product that is cheaply doled out
    to foment hardware sales.
    If you have not been an obedient consumer and purchased a Decent NVIDIA card
    IRay performance will be punishing to the point of essentially being unsable.

    "That's why all of the sampling parameters
    are abstracted away and you cannot set samples on lights independently of each
     other or override shadow behavior."

    This is what I have often referred to as DUMB ,Brute force path tracing.


    That glass/Crystal vase on the side table ,in the background, behind your main subject
    will have no option to reduce the number of bounces to a minimum on that material
     as you would with a branched path tracer Like Blender cycles. 

    And sadly Reallusion has Chosen  to bundle IRay in their latest offerings.
    IMHO the worst possible choice for a user base who is used to realtime animation of 
    people.

    Post edited by wolf359 on
  • Rashad Bryce-CarraraRashad Bryce-Carrara Posts: 1,699
    edited December 2018

    When comparing render engines it's helpful to understand the design goals of the engine creators.  If you look at the official Iray plugin site, you will see how they are marketing the Iray render engine to a very specific market.  Architecture and product visualization.  It is not designed to be a character or VFX render engine.
    https://www.irayplugins.com/iray-for-maya/gallery.php
    https://www.irayplugins.com/iray-for-rhino/gallery.php
    https://www.irayplugins.com/iray-for-3ds-max/gallery.php

    Notice how those galleries are totally unlike the Daz gallery :D

    You can also tell how low character rendering is on Iray's priority list in that there are no built in native hair shading primitives and no 3rd party hair plugin supports Iray (whereas many of them do support Octane and Redshift).

    Iray is also designed for ease of use.  That's why all of the sampling parameters are abstracted away and you cannot set samples on lights independently of each other or override shadow behavior.  The creators describe the design decisions of Iray in this whitepaper "The Iray Light Transport Simulation and Rendering System" https://arxiv.org/pdf/1705.01263.pdf 

    A soup spoon and a tea spoon might look similar and you can substitute one for the other but each has a function that it is better suited for.

     

    Like others I do agree with this observation in a general way. My question though comes in wondering in what ways could an application like Iray be made more accommodating to character rendering?

    There is a Random Walk SSS available in Arnold and a few other higher end rendering applications, not yet in Octane however but it is coming soon. It provides a much better SSS than the usual methods, so even the best Octane renders of skin made thus far will get much better once the new ideal is implemented. However aside from calculation specific differences, aside from energy conservation which is already in place, what more types of tools do we need to make Iray more character friendly?

    Perhaps the addition of the ability to render hair directly in Iray, in a manner not unlike Octane whcih cah import hair curves from other apps and recreate them in Octane's format.

    Thanks for any ideals you might offer.

    Post edited by Rashad Bryce-Carrara on
  • kyoto kidkyoto kid Posts: 30,604

    .. .some older hair content does not perform very well in Iray.  If it is wispy (like April's Osean Hair for example) it will look like the character is suffering from hair loss unless you manually edit the opacity slider to increase parameter maximum above 100%.  Also any hair that has wispy elements like bangs and such will also suffer.

    Slosh's UHT2 hair utility does have an opacity adjustment that auto rests the parameter slider. Sometimes when using UHT2 though, you get odd texture results depending on how the hair maps were originally set up (like the UHT texture orienting applied 90° to the direction of the original map).   

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