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Glowing Head Problem, with subsurface scattering (interjection) addon, DS and Genesis Figure
Posted: 08 December 2012 02:52 PM   [ Ignore ]   [ # 16 ]
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Machieltje, shadow bias affects SSS?  I didn’t know that, why didn’t anyone put that in the documentation???? sheesh…

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Posted: 08 December 2012 02:56 PM   [ Ignore ]   [ # 17 ]
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It’s the flashlight nose/mouth thingy put into overdrive by the subsurface scattering. I had the same problem when I started messing with it and came up with pretty much the same sollutions as are mentioned here none of them really worked but shadow bias did…

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Posted: 08 December 2012 03:04 PM   [ Ignore ]   [ # 18 ]
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I’m doing the test renders now: will post my results.  Thanks for the tip.

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Posted: 08 December 2012 03:12 PM   [ Ignore ]   [ # 19 ]
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Bejaymac - 07 December 2012 08:38 PM

Turn off SSS completely as you don’t need it with humans as we’re not translucent all the way through, the only SSS you need for 99.999% of your renders is already burned into every realistic texture out there.


You’re right humans aren’t translucent all the way through that’s why its a SubSurface scatterer as part of the light is reflected but the skins subsurface. If you want proof that this is a real effect; take a powerfull flashlight, wrap your hand around it and see what happens (it helps if there isn’t a lot of other light so doing in the dark might be a good idea raspberry) Once you’ve seen the difference you won’t want to render human skin without SSS it’s way more realistic.

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Posted: 08 December 2012 03:17 PM   [ Ignore ]   [ # 20 ]
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wancow - 08 December 2012 03:04 PM

I’m doing the test renders now: will post my results.  Thanks for the tip.

No problem, it took me ages to figure this one out thought I’d save people some time :D

btw the effect does not always occur but sometimes the light hits the subsurface in such a way that nose and mouth light up adding an additional light can sometimes make it go away but if you don’t want to do that the only way to get rid of it is by adjusting the shadow bias.

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Posted: 08 December 2012 03:18 PM   [ Ignore ]   [ # 21 ]
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Okay, starting with my own materials, I have made these tests.

My default shadow bias on my lights is 0.1 So I tried my materials at that, and then at a shadow bias of 1.0

bottom is at 0.1, top at 1.0

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Posted: 08 December 2012 03:19 PM   [ Ignore ]   [ # 22 ]
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Now here are the Interjection Light mats

Top is at 1.0, bottom at 0.1
OH: these are Shadow Mapped… it just occurred to me that Raytraced might be different!

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Posted: 08 December 2012 03:23 PM   [ Ignore ]   [ # 23 ]
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wancow try raising your Subsurface scale to help get rid of the lines you seem to be getting on the skin.
Alot of things effect SSS, there doesnt really seem to a one size fits all answer.

Raytraced lights are alot better, DT recommends using them when using Injection

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Posted: 08 December 2012 03:23 PM   [ Ignore ]   [ # 24 ]
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wancow - 08 December 2012 03:18 PM

Okay, starting with my own materials, I have made these tests.

My default shadow bias on my lights is 0.1 So I tried my materials at that, and then at a shadow bias of 1.0

bottom is at 0.1, top at 1.0


Ok so if that is right I’ve identfied a problem I’ve been having with the nasty striping when using SSS raspberry also your lighting setup seems to prevent to glowy nose something I’ve also seen in one of my portret setups.

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Posted: 08 December 2012 03:24 PM   [ Ignore ]   [ # 25 ]
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Yah, I’m learning that! smile

Subsurface scale… is that in the render settings?

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Posted: 08 December 2012 03:26 PM   [ Ignore ]   [ # 26 ]
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scorpio64dragon - 08 December 2012 03:23 PM

wancow try raising your Subsurface scale to help get rid of the lines you seem to be getting on the skin.
Alot of things effect SSS, there doesnt really seem to a one size fits all answer.

Raytraced lights are alot better, DT recommends using them when using Injection

My settings (I found it in the Materials) are currently at 4.  How far up should I go?

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Posted: 08 December 2012 03:27 PM   [ Ignore ]   [ # 27 ]
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scorpio64dragon - 08 December 2012 03:23 PM

wancow try raising your Subsurface scale to help get rid of the lines you seem to be getting on the skin.
Alot of things effect SSS, there doesnt really seem to a one size fits all answer.

Raytraced lights are alot better, DT recommends using them when using Injection

Well, he’s proven one thing; shadow bias does affect SSS :D


Oh and raising the scale as in bigger numbers yes? (been toying with that as well but couldn’t seem to get it right…)

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Posted: 08 December 2012 03:33 PM   [ Ignore ]   [ # 28 ]
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wancow - 08 December 2012 03:26 PM
scorpio64dragon - 08 December 2012 03:23 PM

wancow try raising your Subsurface scale to help get rid of the lines you seem to be getting on the skin.
Alot of things effect SSS, there doesnt really seem to a one size fits all answer.

Raytraced lights are alot better, DT recommends using them when using Injection

My settings (I found it in the Materials) are currently at 4.  How far up should I go?

I have the scale set at 1.7 (the interjection default) and I don’t get the lines except on a char’s thighs….

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Posted: 08 December 2012 03:34 PM   [ Ignore ]   [ # 29 ]
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I’ve never had to go above 4.
Your lights seem very bright to me and raising the bias seems to have helped but it might cause problems elsewhere with shadows.
I often find it is a act of balancing several things.

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Posted: 08 December 2012 03:43 PM   [ Ignore ]   [ # 30 ]
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It’s raytracing that gets rid of the lines.  It seems those lines come from Shadow Mapping.

Here it is, Shadow Bias 0.1 with ray traced shadows, my materials.

HOWEVER: it looks a lot like the Raytraced Shadows set at 1.0, but without those lines… interesting… I’ll play with the scale and see what happens.

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