Working With Joel's Skin Shader Demo

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Working With Joel's Skin Shader Demo

Postby DrHas » Mon Mar 16, 2020 7:53 am

Eve everyone, well it is evening here in Oz lol! I hope everyone is keeping safe...fucking Coronavirus. I remember when Corona was a weak as piss Mexican beer, but enjoyable enough really cold on a hot day with a slice of Lemon lol! Too soon for corona jokes :)?

Anyway, if there is anyone left alive still enjoying Makehuman - Animation is at least a safe form of content creation lol! - but for anyone still interested, I've been busy experimenting away with the skin shader Joels, the guy who seems to the honcho around here, demo skin shader. You can find it in the download section of this website and in the mis category I think. I didn't quite know where to post this, because there has been a lot of discussion regarding skin pores and a more realistic skin.

The good news is, the skin shader does work really well for skin pores, and probably a more realistic skin. The issue is without better instructions, on what each parameter actually does - the process is very random. I also had to re-wire the shader into the Blender Cycles pipeline, taking the place of the original. The alpha wire (off the top my head) needs to go into mix amount socket. I will have to check this though. If you don't wire the shader properly - the skin becomes lighter.

You also have to know how to light a scene well (tri-lighting), and on top of that a basic understanding of photography/cinematography. Oh, and using the World tab which means you've got to set the tri-lights first (this is how I get the best results), then use a HDRI image for the overall light...again this is how I got the best results. Firstly, before you bring the World lights up, you turn the ambient occlusion on...turn down to the desired effect...pretty low because you're going to introduce the overall lights. Then turn up the world lights. Make sure you feed the enviroment node into a background node which gives you control of the brightness. I only ever used a 0.300 setting...but it is enough to put highlights in hair and the like. Just like photography, you might want to put some shading above the characters head.

I've attached two example images, to show the skin shader in effect. Both images were rendered with 1000 overall samples, 10 max samples and 6s, 8s, and 2s for the rest of the lighting. I will have to a proper tute on this. I'm working on getting a second computer for this.

I've just remembered - I turned the sub-surface modifier on at least the Trump image lol. I was experimenting, due to the fact skin can sometimes not be to smooth. Maybe...I'm a mad scientist!

Image one is indeed a model I did of Donald Trump. This model is for the Gay Bar (song) cover I'm looking at doing after my Stand Deliver cover...again with Trump as The Highwayman!

The second is Udo Kier as one of the scruffs The Highwayman will rob in the animation of Stand and Deliver lol.

Hope this helps some of you and who have been interested on this topic.

I will post the Overture of my animated Star Trek symphony in a few days.

Stay Safe and Don't Panic!

Actually image one is Udo and image 2 is Trump lol. The pore definition is better on Trump. The issue is 8-bit jpegs. I do all my animations at 32bit Open EXR. I've got to upgrade mu photo editing program!
Attachments
UdoJpeg.jpg
TrumpGayBarKiss.jpg
DrHas
 
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Re: Working With Joel's Skin Shader Demo

Postby DrHas » Thu Mar 19, 2020 2:20 am

Hi all, still here - coronavirus hasn't got me yet lol!!

Ok, I've figured out Joel's skin shader better. See below image. As always, there is a formula and it goes like this - increase the subsurface modifier along with the poor shader controls to increase poor visibility. I'm still working on this formula though. This is because, for the Trump image below, I've set the subsurface modifier to one and increased each of the pore modifiers. I suspect that when you have older models with older skin - the formula works in the opposite way. Whereas when you have younger models and skins - to iron out the creases which is probably a by-product of adding too much of these features when modeling, you have to increase the subsurface modifier to 4. And this is why I think there is a formula you can follow - when the subsurface modifier is only set to 2 and it's on a young model with a younger skin...even increasing the pore parameters doesn't allow the pores to show properly. It was only when I increased the subsurface modifier that the skin shader worked like it should. I should also mention that to get a more realistic skin (something you can just being to see in below image, the skin looks fantastic when it is a 16-bit png...below image is only 8-bit), if you change the clearcoat and roughness settings.

Again, I used 1000 overall samples with 6-8s for individual lighting settings or diffuse ect. I only use 1000 samples for test renders of individual images too. For animations, I use 100 samples for close-ups and 50 for mid-shots. If you set the denoiser correctly - only a trained eye can tell the difference.

You should set the colour management to filmic log - both image and sequencer. I can only tell you the difference is night and day if you don't. As an example, I finished a 3 minute animation only a few days ago and of which I will post soon. I set the image to filmic log, but not the sequencer. The animation still looks great -I started re-animating the first movement of AV symphony and of which the 3 minute animation is the overture. This time I set the sequencer to filmic log...and I was blown away. The realism now when animating my Makehuman character is off the chart. I mean it's still an animation - but the softness of the skin really shines through as do other features!

Please stay well, and don't panic. And lets all chant 'fuck you coronavirus' lol!
Attachments
Trump 2.jpg
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Re: Working With Joel's Skin Shader Demo

Postby joepal » Sun Mar 22, 2020 1:23 pm

It's also important to know that the subsurface multiplier is directly related to scale. If you import at 1 BU = 1 meter, the multiplier should be somewhere between 0.1 and 0.4, but if you import at 1 BU = 1 decimeter, it needs to be multiply it by ten, so that it is between 1.0 and 4.0.

But all this makes me realize I should probably add more descriptive tooltips to the shader settings.
Joel Palmius (LinkedIn)
MakeHuman Infrastructure Manager
http://www.palmius.com/joel
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Re: Working With Joel's Skin Shader Demo

Postby joepal » Sun Mar 22, 2020 2:09 pm

Anyway, surprisingly much in skin realism comes from proper lighting. Here I haven't done a whole lot apart from setting lighting and adjusting a few values in the skin shader:

skin1.png


I adjusted colors to get a slight tan for the skin color of the usual bundled caucasian female young 2. I also changes roughness to 0.4, which will make pores more visible when you have light coming in from the side. For a character of this volume, I increased the pore scale slightly.

skin2.png


It's by no means perfect, but you only get so far with a procedural texture. To get more realistic details, you'd probably need a more hand-crafted bump map for pores and facial features.

Note however, that with the latest version of the shader, you can get material slots automatically assigned for different vertex groups of the body. In the image, i have different settings for the lips:

skin3.png


Here, I have reduced the pore scale to get larger bumps, and included a more reddish skin tone.

You can find the checkbox for enabling extra vertex groups under the "extras" setting on the settings tab in the importer.
Joel Palmius (LinkedIn)
MakeHuman Infrastructure Manager
http://www.palmius.com/joel
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Re: Working With Joel's Skin Shader Demo

Postby DrHas » Mon Mar 23, 2020 8:25 am

Hey Joel, great thanks for all the information. I will have to download the updated skin shader too.

Yes - lighting is key.

Keep Safe.
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