Going for realistic face render

Kgizzi

Sculpt based off of a model from a Scott Eaton tutorial. The Displacement map is 8k but all other maps are in 4k so as I update them into 8k I may try another render again later. Any advice welcome.

bkost

Hey @Kgizzi its Blake from Artstation. May i see your snippets of your spec, roughness, and displacement? I recommend checking out Arvid Schneiders tutorials on youtube for Arnold skin shading. They helped me out a ton. I haven't touched offline rendering in awhile, but I'll crit as best as i can. 

Oh and seeing your node setup would be nice. Cheers

Kgizzi

Hey Blake. I do a lot of my work from my laptop and do the rendering on my home PC and I won't be back there until Wednesday where I have all that stuff on there. For now though I've made some general notes of the way I do it, which is the same as the Tom Newbury method from his gumroad tutorial.

So you start with 4 different RGB channel masks from Mari with different masks in each of the red, green and blue channels. So the first of the RGB masks is made up of 3 different cloud channels to give breakup to the surface. The second RGB mask has a Tmask in the red channel, eye wetness in green channel, lip and ear mask in the blue channel etc. So basically I take these channels and use them to drive the Spec Color and Roughness on the skin shader.

like that. The top left hand corner has the 4 different RGB channel mask textures which are being plugged into the Remap nodes you see here in the Hypershade. I don't have formal 3d training so I know I'm not using proper terminology in some places, but yea for now that's the best I've got lol. Any help you can give would be appreciated

Kgizzi

Also Blake, do you think I have enough SSS going on in this image? I'm being told be some people it's ok and others say there's not enough. I keep trying to minimize the SSS because it keeps blowing out my details, not sure what to do about that.

Kgizzi

Just bumping this one more time if anyone can give me any recommendations on what to improve. This is one of my first renders in Arnold and when you're self-taught it's not easy to figure out what you're doing wrong. Like comparing my own renders to someone like this I'm not sure where to go about beginning to bridge the gap: https://www.artstation.com/kubisi

bkost

Hey @Kgizzi apologies for the late reply, I wasn't notified you commented. It's good to notify others when chatting with @[insert name].

Regarding the issue of shallow displacement maps and the light not catching. I suggest incorporating a cavity map if you aren't already. I normally overlay my cavity onto roughness and spec maps to help create 'depth' by making the pores not catch any light. I am by no means an expert. I recommend checking out the wonderful tutorials posted up on texturing.xyz's website. For the SSS washing out your details, try making a masking map. With this map you can tell which areas of the face need more SSS (like the ears, nose, and eyelids) 

Alex_J

i don't know nothing about offline rendering, but I agree a cavity map will help with details like pores and blackheads against the SSS. You can create a cavity map without baking if you did your sculpt in zbrush and it shares UV's with the low poly. Simply fill the tool with white polypaint, mask by cavity, invert mask and fill black polypaint, and export your texture map.

Then the cavity mask can get plugged in so that it takes away from diffuse color and/or specular highlights. This is how it works in Marmoset Toolbag at least.

Kgizzi

bkost said:

Hey @Kgizzi apologies for the late reply, I wasn't notified you commented. It's good to notify others when chatting with @[insert name].

Regarding the issue of shallow displacement maps and the light not catching. I suggest incorporating a cavity map if you aren't already. I normally overlay my cavity onto roughness and spec maps to help create 'depth' by making the pores not catch any light. I am by no means an expert. I recommend checking out the wonderful tutorials posted up on texturing.xyz's website. For the SSS washing out your details, try making a masking map. With this map you can tell which areas of the face need more SSS (like the ears, nose, and eyelids) 

Hey thanks for the reply @bk@bkost I am using Arnold following Tom Newbury's tutorial found here. He doesn't use any sort of cavity maps specifically, just a displacement export from Zbrush then the pore displacement from Mari. Thanks I'll try to get into some of those XYZ tutorials. I actually do have a mask on the SSS map, it's pretty much an inverted ambient occlusion map I think so it focuses the SSS on the ears, eye region, and nose, where the light passes through the most in life. I'm thinking I just need to make the wrinkles and details a little bit more dramatic in my models if I know I am going to be rendering them with SSS in the future...

Kgizzi

BIGTIMEMASTER said:

i don't know nothing about offline rendering, but I agree a cavity map will help with details like pores and blackheads against the SSS. You can create a cavity map without baking if you did your sculpt in zbrush and it shares UV's with the low poly. Simply fill the tool with white polypaint, mask by cavity, invert mask and fill black polypaint, and export your texture map.

Then the cavity mask can get plugged in so that it takes away from diffuse color and/or specular highlights. This is how it works in Marmoset Toolbag at least.

So wait you're saying too mask out the cavities themselves so the valleys within the skin aren't getting the SSS but the peaks DO get it?

Alex_J

I don't want cause confusion. Let me restate more clearly :

The cavity map is a black/white mask, black being the small cavities like pores or very fine wrinkles. The black part of the make occludes specularity and/or diffuse color. It works somewhat similar to an AO map.

So it is not acting against the SSS directly. It is masking diffuse color and specular highlights.

This tutorial is where I learned about cavity maps. It's for Toolbag but it may still be useful for you :

https://marmoset.co/posts/creating-realistic-skin-toolbag-saurabh-jethani/

Kgizzi

BIGTIMEMASTER said:

I don't want cause confusion. Let me restate more clearly :

The cavity map is a black/white mask, black being the small cavities like pores or very fine wrinkles. The black part of the make occludes specularity and/or diffuse color. It works somewhat similar to an AO map.

So it is not acting against the SSS directly. It is masking diffuse color and specular highlights.

This tutorial is where I learned about cavity maps. It's for Toolbag but it may still be useful for you :

https://marmoset.co/posts/creating-realistic-skin-toolbag-saurabh-jethani/

Ah ok thanks for the reply. Yea I'll see if I can figure out how to convert any of that into Arnold for Maya. I might just want to try to get Marmoset in general though, people seem to get nice results with it.

musashidan

The disp details getting washed out by the SSS effect is normal. The maps in the reflection layers will counter this. It's vitally important that you balance these 2 layers under good lighting conditions.

My advice is to turn off SSS and just work on the Spec 1 and 2 maps and Rough(gloss) 1 and 2 layers. These are the key. These layers will always preserve details even at mid-far distance(especially sheen layer)disp/normal/bump will not, so this is what's happening with your detail fading out. In the alsurface shader the reflection layers are the opposite of other renderers so that the sheen layer is actually layer 1. Also, the 3 scatter layers are arranged unintuitively with SSS3 being the epidermal, SSS2 being the deep layer, and SSS1 being the sub-dermal. The density scale has a significant impact too.

Lighting plays a massive role as well. Flat, soft light will wash out your details, as will diffuse image based lighting with no contrasting light sources. Try turning off the image based lighting and create a 3-point lighting setup. Work on these 1 at a time so you're not distracted by too many lights at once. Also, the rim light will give a good indication how much SSS is affecting the shader.

As for the cavity map, this can be used as a base to build your spec/gloss maps. If you have a microsurface map this will be particularly useful for your spec 1 rough/gloss map.

A handy tool is to add in a reflection and translucency(sss) AOV composite element and switch between passes in the frame buffer.

Another thing is try to do a lot of the work in the shader using remap nodes. This way you're not constantly painting/tweaking maps in mari or zbrush or painter. With Arnold IPR you gt instant feedback if you're tweaking the shader.

Try not to get sidetracked by Marmoset Toolbag, stick to offline methods and techniques. Offline rendering realistic human skin is a whole other beast than real-time and a lot more shader-focused.

You've done a great job so far. Offline character rendering is an involved process involving insane amounts of look-dev tweaking so stick at it, you've all the parts in place so it's just a matter of stepping back, breaking it down, and concentrating on 1 thing at a time so you don't get overwhelmed by trying to get all the components looking right at the same time. Your first port of call should be the spec/gloss maps. Get those right and you'll be well on your way.

musashidan

One other important thing I forgot to mention. Make sure to set your alsurface shader SSS to Directional. It's the most expensive, but also the most accurate. It will give much better results than default Cubic and will retain more of your details. I'm right in the middle of look-dev on a portrait sculpt too. Going through all the same pains as you.

Kgizzi

@musashidan Cool thanks a lot for the help. Yea I have Micro detail from the Displacements going into the Specular roughnesses. I usually have trouble with that area though because for some reason the "Tmask" which focuses the glossiness onto the nose, cheeks etc tends to get overly punchy and hard edged for some reason when I do lookdev not sure why. I'm not home with my PC right now, but on Wednesday I will be so I'll post some images of what the Soec1 and Spec2 remaps look like on the model as well as what it looks like with the diffuse shader and SSS turned off. I too have a feeling that that's where I'm having an issue as well as the general tightness of the lights. I am running a 3 light set up as well as a HDRI skydome for the fill light. I'll post a screen of my set up too so hopefully you and anyone else can see more of what I'm doing and where I might be falling off. Thanks again for the insights.