skin shader a la Alsurface pleaseeee

[Bigguns]

Hi there,

at my new job, they are using Arnold and I'm impressed with the Alsurface shader, I was able to play with it and it's MUCH better then in Vray..sorry.

Here are some doc about it :http://www.anderslanglands.com/alshaders/alSurface.html https://leegriggs.files.wordpress.co.../alsurface.pdf

Can we get something VERY similar ( if not exactly the same ) in Vray ? You need to play with it guy's at chaos group, you'll see what I mean.. just compare it to the sss2 and you'll see..

I also like a lot the fact that you can choose between ( now ) 4 differents types of scattering, I really like the Directional one and the latest they added is nice too depending on the reaserched look. Also I like that the sss layers don't affect the overall color ,etc. The skin feel more translucent then in Vray , in Vray it look's way too opaque .. The standard arnold skin shader suck.. really bad.. ALsurface saved arnold.. no wonder why so many peoples use it,.. remove alsurface and.. we would not use it at work lol.

I think right now the biggest advantage arnold has over vray is that shader.. other then that.. Arnold is really slow to render interior.. where vray is much faster.. they would maybe use Vray if it had the same skin capability's.. it's important when you do characters to have the best skin around so.. for now it's alsurface that does it.

Let me know guy's

thank's

[Morbid Angel]

that skin does look impressive. Wondering if any one cares to do a vray comparison

[vlado]

Well, it should not be terribly hard to get something similar...

Best regards,
Vlado

[Bigguns]

Then great to hear that Vlado! I'm looking forward to it!!!! Loads of peoples I know would be very glad to have it soon!! and also to 2d displacement to support udim in max!

[kagemaru]

I had the pleasure to work with Anders and i can tell why so many people like his stuff. They are heavily production oriented and smart in a lot of way. I can't tell about his work with Arnold (we used prman back then) but his tool have always been amazing and really productive.

[Bigguns]

Maybe Vlado you can ask this guy some help to set up something similar in vray ? Would be really awesome seriously... I guarantee you that if Arnold had not that Alsurface shader.. a LOT LESS studios would use it.. trust me.. starting from the studio where I work..

[^Lele^]

Hi there,

at my new job, they are using Arnold and I'm impressed with the Alsurface shader, I was able to play with it and it's MUCH better then in Vray..sorry.

Here are some doc about it :http://www.anderslanglands.com/alshaders/alSurface.html https://leegriggs.files.wordpress.co.../alsurface.pdf

Can we get something VERY similar ( if not exactly the same ) in Vray ? You need to play with it guy's at chaos group, you'll see what I mean.. just compare it to the sss2 and you'll see..

I also like a lot the fact that you can choose between ( now ) 4 differents types of scattering, I really like the Directional one and the latest they added is nice too depending on the reaserched look. Also I like that the sss layers don't affect the overall color ,etc. The skin feel more translucent then in Vray , in Vray it look's way too opaque .. The standard arnold skin shader suck.. really bad.. ALsurface saved arnold.. no wonder why so many peoples use it,.. remove alsurface and.. we would not use it at work lol.

I think right now the biggest advantage arnold has over vray is that shader.. other then that.. Arnold is really slow to render interior.. where vray is much faster.. they would maybe use Vray if it had the same skin capability's.. it's important when you do characters to have the best skin around so.. for now it's alsurface that does it.

Let me know guy's

thank's

I think V-Ray can match anything Arnold can throw at it.
While perhaps some of the SSS methods may not be identical, you'd be hard pressed to show the difference as appreciable in most cases.
And that, without taking into account what the render cost would be, either way.
The render of Emily below took an hour on an old 24 cores xeon (fullHD, vertical.), to full sampling at 0.005 noise threshold (meaning, every pixel in the image achieved that noise level, measurably so.).
I shall lie in perennial wait for an arnold scene of the (public.) data with the same resulting noise level to benchmark against.
I know the difference quite exactly indeed, but i shall keep it to myself.



The shader is fully energy preserving, layered (2 SSS, one specular. and not for lack of options either.), and properly behaving (if you want, i could state it slightly differently, like they do on the SA site.) under all lighting conditions, on top of being supremely finely displaced (adaptive displacement to 1 pixel in edge size).

I scripted one such layered shader in Max two years ago, albeit i only ever showed the UI to the public, in the vein of what the Pixar Principled shader was, and honestly there was very little lacking from our side, if anything: in fact, we did correctly also refraction, absent in the Disney one.

One thing which we do miss is the ability for the blend material to be automatically Energy Preserving at the top, but then that does pose a number of related questions (clamp, scale? And how?) which often can't be simply answered in advance and have to be left to the user's choice and good sense.

So, if you want, i could surely adapt you that scripted shader to incorporate just what the aiShader has, but i personally loathe, no less, the approach based on ubershaders.
So i wouldn't be doing it with a sparkle in my eyes.
Besides, it seems to me it's built to fix shortcomings into the standard aiShaders, more than anything else.
Limitations we don't share, fully or at all.

edit: this scripted shader.
http://forums.chaosgroup.com/showthr...153#post657153

[Bigguns]

First ,I'm not talking about the aiskin shader that come with arnold by default.. that one is really bad.. I'm talking about the ALSURFACE shader .. that one is really cool.. especially in Directionnal mode , for skin its better. ( directionnal mode should be added to the sss2 ASAP )

What makes it better then vray is a few things : First, we don't have much sss bleeding like in vray ( with the sss2 or the vray skin mtl ) , so lets say, sss bleeding around the upper eyelid fold, or between the lips etc.
Secondly, reflection is better by default.. sss2 reflection are bad ( way too much fresnel effect going on ,no ggx ,etc etc. ) and you have to blend it with some layers with the vray blend to get something better ( but still not physically perfect.. )

In third, in Alsurface surface, the diffuse color is the only thing that affect the overall color.. ( like in sss2 )unlike the vray skin shader that you'r overall color is splitted into the 3 different sss layers.. wich make it impossible to get exactly what you want for the overall color and make it painfull to just try to get there..

plus, alsurface has a better feel to it, it feel more depth.. less opaque then vray sss2 or skin mtl . It feel's more like skin. the way they builded the alsurface is just better.. and also, I like that you have the choice between 4 types of sss, like cubic,directionnal,diffusion,etc. It's really cool shader.

Also, Alsurface get much less greener when you boost the sss value then the sss2 or vray skin mtl.

BTW I don't like you render of emily, she look's plastic, I don't feel any front scattering here and the reflection are flat.. I don't think it's a good exemple of vray skin capability's.

[^Lele^]

What makes it better then vray is a few things : First, we don't have much sss bleeding like in vray ( with the sss2 or the vray skin mtl ) , so lets say, sss bleeding around the upper eyelid fold, or between the lips etc.

So, of the four modes, here, you're talking of the Directional one, right? Particularly as it seems to be the only one to possess single-scatter, of the four in question.
Or do all measurably preserve detail as well?
Could i see obvious examples of that behaviour, when compare f.e. to live reference material of the same subject?
Emily and all the accompanying material ought to be fairly easy to convert for an Arnold expert: the scene comes in maya and max versions, and shading and lighting ought to be a straightforward matter.
Plus, it comes with heaps of references, so a match can be done by the numbers, rather than by eye.

Secondly, reflection is better by default.. sss2 reflection are bad ( way too much fresnel effect going on ,no ggx ,etc etc. ) and you have to blend it with some layers with the vray blend to get something better ( but still not physically perfect.. )

The inability to choose the BRDF for the spec inside the SSS2 is indeed an annoyance to me too.
This said, creating a blend with an additive ggx layer is trivial.
As for "not physically perfect", i'd like to hear more of the specifics, for perhaps there are ways around limitations other than a full rewrite (i.e. matching an ior, adding a map, bumping both together. i'd really like to hear what it is you're referring to.).

In third, in Alsurface surface, the diffuse color is the only thing that affect the overall color.. ( like in sss2 )unlike the vray skin shader that you'r overall color is splitted into the 3 different sss layers.. wich make it impossible to get exactly what you want for the overall color and make it painfull to just try to get there..

From the link you provide, it looks to me like the SSS part is identical to the vray skin shader (minus the scatter modes): one diffuse, three sss, two spec colours and layers, all additive, all weighted.
Could you show me a comparison, or a sample of where the skin shader fails?
I found that most of its defaults tended to be a bit over-saturated, and that it behaved much better with slightly more muted tones.
I personally prefer to layer my shader by myself, using a blend, as there is no performance penalty, and greater control.
But i agree, more work could be done for some of the UI parts.

plus, alsurface has a better feel to it, it feel more depth.. less opaque then vray sss2 or skin mtl . It feel's more like skin. the way they builded the alsurface is just better.. and also, I like that you have the choice between 4 types of sss, like cubic,directionnal,diffusion,etc. It's really cool shader.

I'd really really love to see a comparison, with scenes, ideally, to see which part comes up short.
Besides diffusion profiles choice, which can indeed make a marked difference in the result, the setup is really similar to the vrayskin, and any other layered, packaged shader of the type.

BTW I don't like you render of emily, she look's plastic, I don't feel any front scattering here and the reflection are flat.. I don't think it's a good exemple of vray skin capability's.

You're right, Emily isn't the best use of any of VRay's SSS capabilities (by design from the authors: the single-scatter is map-approximated, not calculated, and the spec map isn't normalised in the distribution.).
However, there are huge contacts sheets i posted from the article i wrote about shading it, which show how it's the subject's skin being oily, and the match is seriously high between reference photos and renders, under the same lighting (a dreadful frontal flash setup, which however serves the purpose very well.).
Not perfect, no, due to a few approximations along the way in rebuilding the reference scene exactly, but quite indistinguishable by features.

As i was referring to in my post, usability is also about the time to get there, the rest can be refined somehow else when there's time left over.
My Emily scene is available in max form, ready to render as per the reference material provided with the original data.
I remain curious to see measurable differences, and most of all some performance data independently verifiable in the form of a usable scene (again, Emily's three quarters of the way there.).
This non-withstanding, personal preference is allowed (i'm being a d*ck ), and there are lessons to be drawn from some of the arnold's UI design choices, i feel.

We'll soon enough see where this will go...

[vlado]

Luc is right, Lele - the V-Ray skin shader has two drawbacks - lack of glossy Fresnel and lack of an overall multiplier. Both are fixable though.

Best regards,
Vlado

[^Lele^]

Are they not both fixable through simple layering, already?
EDIT:i'm asking because if that's the case then the scripted, layered shader already had it done properly. I'd only have to cook it for skin, rather than disney-principled)
EDIT2: unless you refer to the micro-facet domain, then nvm.
I was more curious about the differences in diffusion profiles, if perhaps Arnold has methods which really show an appreciable advance in the distribution...

[vlado]

Are they not both fixable through simple layering, already?

Not really.

I was more curious about the differences in diffusion profiles, if perhaps Arnold has methods which really show an appreciable advance in the distribution...

I don't think that the actual diffusion profile makes much of a difference.

Best regards,
Vlado

[^Lele^]

two different things mixed, eheh.
So, to be clear, we're talking of spec taking micro-facet fresnel into account on one hand (did i get it right?), while i was curious as to how the four diffusion profiles behave in terms of light distribution and detail preservation.
I may just go ahead and convert Emily myself (and will have to grab an AiSurface.) for the latter part.

[Bigguns]

Lele, don't grab Aisurface. take ALshader here : http://www.anderslanglands.com/alshaders/index.html( BTW , the way that material is build is awesome, you can do a lot of thing with it.. skin, metal,glass,etc not hairs though, that's why they added a alhairs ) , I posted the link in my first link .. the standard skin shader in arnold suck.. dont even bother with that one.

The alsurface in directionnal mode retains more details then the vray sss2, has better back scattering, less sss bleeding , better default reflection especially the fresnel , feel's more dpeth to it,better back scattering , less greenish with high sss radius, the 3 sss color don't affect the overall color like in the vray skin wich makes it WAY more easy and better looking then the vray skin..etc etc. I cannot do a render comparaison , I use max.. and it's not available ( for now ^^ since autodesk buy solid angle.. we will have it sooner then later.. probably next year ) , but at work guy's do shading in Arnold.. and I saw it.. I know the result of the sss2 by now... so I can compare easily the feel of both.. strongness and weakness.. what would be cool also for a new skin shader in vray would be to have control of the sss in shadow region, in reality it get redisher.. wich we don't have now.. we just have a redish line in the transition between lighted and shadowed region. Also, have a first scatter layer that does glossy refraction to see the fur going fading through the skin would be awesome.. the alsurface don't do that.. that would be awesome to have.. would help tremendously to integrate better all the eyebrows, eyelash etc on the face of a character.. because now they feel like pasted in 2d over the character..

And yes Vlado, the method distribution make's a huge difference, you should play with the shader, you'll see. In directionnal, it look's way better for skin.. the devil is in the small details you know

[Bigguns]

and here, at the bottom of the page, this guy made a comparaison between cubic and directionnal and it clearly shows that directionnal for skin is much better https://leegriggs.wordpress.com/page/3/ even though this guy is really bad at rendering skin...