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SSS shaders
Posted: 03 May 2013 04:40 AM   [ Ignore ]   [ # 61 ]
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Szark - 02 May 2013 09:31 AM

Sorry I did get a notification of a reply and forgot about it, my bad. I am a tad buyt at the moment…visitors due soon, well there are here now.

I will try to reply later.

Thank you! smile

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Posted: 03 May 2013 09:11 AM   [ Ignore ]   [ # 62 ]
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Thank you Szark and Richard for the information about groups, I hadn’t understood this yet either smile

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Posted: 03 May 2013 10:12 AM   [ Ignore ]   [ # 63 ]
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Developing my SSS Settings… this one has 100%SSS with 40% Diffuse… I know that does not add up to 100%... I’m working on developing the shaders I want to use for all my figures.  I had to jack up the light intensity back to 100% for the Key and UE2, 50% fill and 200% Back and I added a Speclamp above and to the left of the camera.  I’m going to have to do something about the hair.  I was conversing with Jim-Zombie on DA and it occurred to me, that when we’re talking about Specular and Reflection, you have to consider the surface before you add it into the mix.  My thought is this: with skin, specular and reflection should go together, but NOT with Diffuse and SSS, as it’s most often a function of moisture and/or oil on the surface of the skin, therefore it is not the same surface.  The same would be true of Varnished wood.  Metal, Opaque Plastic etc would, however, require that you have DIffuse, Spec and Reflection all be part of the same surface formula since those are hard surfaces with no subsurface.  Cloth would be the same, with SSS added into the mix…

Anyway, still trying…

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Posted: 03 May 2013 02:46 PM   [ Ignore ]   [ # 64 ]
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There’s a simple answer to this. Bring it into a photo editing program and check out the histogram. If it’s not getting blown out and it looks the way you want, it’s fine. If trying to make a setup that works for a range of applications, set up test cases of the extremes and some random and run them through, checking visual and histo.

I try to avoid shortcuts that are just off base whenever possible, such as adding ambient to things that wouldn’t have ambient, but there is a point where we are working with approximations to start with, so fudging it almost comes with the territory to some extent. This goes for unbiased render engines also. HDRI is one big fudge for the fact that we don’t have all of the light sources and bounce light we would irl.

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Posted: 03 May 2013 02:59 PM   [ Ignore ]   [ # 65 ]
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We do have GI smile  I have not the first clue how to read a histogram smile

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Posted: 03 May 2013 04:47 PM   [ Ignore ]   [ # 66 ]
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Yes, but GI is a fudge for rl aspects that is impossible to take into account in a realistic manner.. all the surfaces, light sources… irl.

As for histograms, they are easy.. if it’s maxed out anywhere along the line, it’s blown out. You could get a better explanation from doing a youtube search probably where they would demonstrate it.

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Posted: 03 May 2013 07:37 PM   [ Ignore ]   [ # 67 ]
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With gamma correction on 4.5.2.40 beta, SSS seems to be beautifully rendered.

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Posted: 04 May 2013 01:13 AM   [ Ignore ]   [ # 68 ]
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I recently purchased the Brialen character (http://www.daz3d.com/briallen). She comes with both std mats and mats using the UberSurface shader including settings for SSS. The comparison image below is the same character render in exactly the same lighting with the two different sets of material. The lighting was a custom arrangement of InaneGlory lights and was exactly the same for both renders.

Now I did find and correct what I believe is a bug in the USS material settings for the face. The Subsurface color is white with a texture. On most body regions the mat is using a texture that looks like the diffusion texture with a lot of pink or red added to it. In the face the subsurface color texture is the specular strength texture, which is black and white. This seems to be true for the default skin as well as the makeup options.  I corrected the subsurface color texture for the comparison below. It only makes a small difference. It makes the face look a little more pink.

The first thing I noticed is the skin looks darker with the USS shader. I compared how the two shaders were set up.

Diffusion: both seem to use the same texture. The std mats have diffuse strength at 100% and the diffuse color set to 232, 244, 248, just slightly bluish.  The USS material has the diffuse strength at 90%, diffuse color at white and diffuse roughness at 1.00.

Specular: The std mat has no specular texture, spec color at 211, 237, 239 (blueish), strength at 9.7% and glossiness of 68.3%.  The USS material has a specular texture, a color of 203, 219, 255, strength of 15%, glossiness of 10%. The specular texture is pretty dark, so specular is confined to a few regions on the face.The USS mat has specular2 with same texture as specular, color 203, 219, 255, strength of 15%.

Ambient: the std mat has ambient color of 255, 240, 239 (pinkish) and Ambient strength of 31.7%. The USS material has Ambient turned off.

USS mat has Fresnel Strenght at 80%, Fallof 2.6, sharpness 83%.

Velvet color 203, 219, 255, strength 25%, fallof 20

Subsurface is Active: color uses a texture that looks like the diffusion texture with a lot of pink/reds added (this is after fixing bug in face material) and has color white, strength is 10% with a texture map that puts the subsurface effects mainly in the cheeks, refraction 1.3, Scale 1.7.

Translucency is Active: color is white with a custom texture. It look kind of like a washed out version of diffusion texture. The strength is 25% with a different texture that looks very similar to the Subsurface strength texture, putting most of the effect in the cheeks.

I really don’t understand why all these settings are the way they are. The ambient is high in the Std shader, and I guess the bluish color in the diffusion is to correct for the pink color of the ambient.

This skin uses strength maps that confine the subsurface and translucency effects to the cheeks.

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Posted: 04 May 2013 04:14 AM   [ Ignore ]   [ # 69 ]
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If you watch Omnifreaker’s videos you will see where he talks about this in US2. I’m sure some of the same type of issues existed in US1 in that because the way the shader works with light, it will get darker and will need to be adjusted and is not a bug. Understand, when switching shaders just like switching render engines, things change and we have to adapt our item to that change. It isn’t a free, slap it on and it works kind of thing. I think this thinking comes from the idea of people doing the ctl click thing, that it doesn’t ‘replace’ materials. But that’s just it, it’s just ‘not replacing materials’... it’s not automatically adjusting settings that are there that weren’t in the previous shader. It still needs to be tweaked. Some people are fine with what the get without going to the trouble of tweaking it, some tweak it without thinking about it…

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Posted: 04 May 2013 04:28 AM   [ Ignore ]   [ # 70 ]
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On the question of Specularity and UE. I just saw a video posted earlier in one of these thread that covered this and unfortunately hadn’t processed what he was saying fully. Basically he was showing, with examples, how UE does not provide specularity, or at least not near the level of specularity one would get from a directional lighting source, so that was exactly why one would want to add a specular only camera. That is, UE is basically an omnidirectional light source. It provides AO but not very strong directional lighting. With any omnidirectional lighting one would want to add back the specular lighting at times one doesn’t see from the omnidirectional lighting. Now, if using omnidirectional lighting to mimic rl type settings, one wouldn’t be getting specular anyways from that type of lighting so ... it comes down to artistic enhancing of that aspect in the end anyways (which we do in photography through various means.)

The whole point of a specular only camera is to enhance specular in a particular way we want that the lighting doesn’t provide. It’s that simple, no math need apply. The thing to keep in mind is, any time we are doing this type of enhancement we want to err on the side of subtle usually. If someone sees our picture and says ‘there’s too much specular,’ I can assure you, they didn’t do any math, they just saw it was too much.

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Posted: 04 May 2013 04:37 AM   [ Ignore ]   [ # 71 ]
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Sertorial I haven’t forgotten just not had the time to sit down and dig out my eyes settings. I will try today.

Mark128
Why are you using Fresnel on Skin?
Ambient is a cheep way of lighting up shadows etc, I and many people I know that use these shaders do not use any Ambient of surfaces prefering to let the light do that job.
Transluceny is a fake too and as Omnifreaker said himself for skin you don’t need to use it.

Diffuse colour. Putting the diffuse to White will increase the red that is in the skin texture, hence way it was blusih origianally and why it is more pink. The red we try to inject with SSS so my advice is drop the red in the diffuse colour channel.
IOR for skin is 1.39 - 1.14
SSS scale try 0.50

There is not right or wrong way to set all this up just good and bad results.

For anyone that really wants to learn this stuff then learn about the real thing. It is all out there. All IOR values are out there too for all body parts. This setting up these shaders is a balance between each channel, many subtle but the trick is not to over do colours, keep them staturated as much as you can. Always set up you skin in white light.

And have you noticed the ON/OFF toggle for each channel. Good way to test things is to remove the skin maps and then turn off all the channel barring one and test render, turn that off, turn another on and test render. This way you will see the effect without the other effects getting in the way. Also when testing each channel change the colour to a very extreme bright colour this will make the effect more visable.

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Posted: 04 May 2013 04:41 AM   [ Ignore ]   [ # 72 ]
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Just watched Omnifreaker’s video on UE2 yesterday, he mentioned using Fresnel instead of something like translucency, to get the ear type thing. That is, if one wants translucency type of effect on something thick like skin they would use Fresnel is what I gathered from it. Translucency being for thin items ‘like paper or leaves’ was his quote iirc.

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Posted: 04 May 2013 04:48 AM   [ Ignore ]   [ # 73 ]
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Gedd - 04 May 2013 04:28 AM

On the question of Specularity and UE. I just saw a video posted earlier in one of these thread that covered this and unfortunately hadn’t processed what he was saying fully. Basically he was showing, with examples, how UE does not provide specularity, or at least not near the level of specularity one would get from a directional lighting source, so that was exactly why one would want to add a specular only camera. That is, UE is basically an omnidirectional light source. It provides AO but not very strong directional lighting. With any omnidirectional lighting one would want to add back the specular lighting at times one doesn’t see from the omnidirectional lighting. Now, if using omnidirectional lighting to mimic rl type settings, one wouldn’t be getting specular anyways from that type of lighting so ... it comes down to artistic enhancing of that aspect in the end anyways (which we do in photography through various means.)

The whole point of a specular only camera is to enhance specular in a particular way we want that the lighting doesn’t provide. It’s that simple, no math need apply. The thing to keep in mind is, any time we are doing this type of enhancement we want to err on the side of subtle usually. If someone sees our picture and says ‘there’s too much specular,’ I can assure you, they didn’t do any math, they just saw it was too much.

Yes that is true UE2 does not give good spec or directional shadows. I have never seen a HDRI that will produce directional shadows light the sun does hence why all the HDRI set in the store have distant lights included. But UE2 does and can blow out specualar highlights that the additional light makes this is why I also agree using all the lighting set to Diffuse light only and use one Specular only light can give more control over specular highlights.

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Posted: 04 May 2013 04:50 AM   [ Ignore ]   [ # 74 ]
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Gedd - 04 May 2013 04:41 AM

Just watched Omnifreaker’s video on UE2 yesterday, he mentioned using Fresnel instead of something like translucency, to get the ear type thing. That is, if one wants translucency type of effect on something thick like skin they would use Fresnel is what I gathered from it. Translucency being for thin items ‘like paper or leaves’ was his quote iirc.

I haven’t seen the vid Gedd, throw us the link please. smile

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Posted: 04 May 2013 04:52 AM   [ Ignore ]   [ # 75 ]
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Actually just put up a post here which has a few links in it, that one included.

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