Attached Link: http://www.users.on.net/~pkinnane/RealSkinShaderTutorial.html

hi all.. was going to try following the tutorial but I'm lost from the start. I can't find any nodes with the fresnel name. (using poser 5)... where are the fresnel nodes hiding?

divinerain

DivisionRAIN....quote from the tut...."Combined_Fresnel is a maths_functions node. The Fresnel_Spots node is a spots node"...this is in the Fresnel Effect section. Sorry if it's complicated. In the tut I tried to indicate what sort of nodes were used where - but may not have got them all.

Message edited on: 01/30/2005 16:22

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The confusing part is that "Fresnel" doesn't pop up as an obvious label. I may be missing something but I don't really see it either. But I'm not very bright about these things.

MMmmmm, which "fresnel" are you refering to? Give me the context from the tut - and I'll clarify.

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I'll take any freshnel...I can't get the term to show up in any of the nodes. I'm probably looking in the wrong place. So if you take the first occurence of "freshnel" in your tutorial and can point the way to what freshnel is listed under, the rest of the journey will probably be easier. I tried the maths-function but, for some reason, I just don't see it.

Well the first real reference to Fresnel is in the "Fresnel Effect" section....which reads "Combined_Fresnel is a maths_functions node. The Fresnel_Spots node is a spots node"...so it tells you what nodes to use to get the fresnel effect. To get your Combined_Fresnel node, simply add a maths_functions nodes, and enter the parameters as per the screen shot. I've renamed the node name from "math_functions" to Combined_Fresnel in the screen shoot so you can tell what node are doing what.

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Ahhhh....you renamed the node! :) I missed that. Thanks!

renamed the node... that explains why I didn't find anything called fresnel in the math functions. Thank yas, I was about to overreact because I thought my copy of poser was missing all the fresnel nodes.

divinerain

Me too. :) I'm glad the answer was a simple one.

I actually don't know how the node was renamed, though.

The script that builds the node network actually renames the nodes so that the whole network is readable. Unfortunately you can't rename a node through the P5 material room.

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You have been ever so helpful and patient. Thank you so much for the clarification. :) I do own the real skin shader and it's just amazing. I compliment you on helping Poser continue to evolve.

I came back to this thread to ask how you were able to rename the nodes. Can't wait til spring gets here, then I can get the real skin shader.

divinerain

Short of the script, I'd be tempted to make up the shader, save as a Material, and then edit the node-names. But at the price the script is, ask how much your time is worth.

Apart from putting in a couple of Math nods when they should have been Colour Math... It looks like you have to tweak spot sizes to get the look of the body and the head matching. Usually the head is a lot bigger on the UV plane than the body. Am I right?

AntoniaTiger, regarding the spots....That was what I thought too. However when I made the spots larger for the head materials, it looked very wrong....so I changed them back to being the same as for the body. I don't really have an explaination for it....

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Well, a part of the problem I'm seeing may be from working with non-human skin tones. AD&D players may have heard of Drow. But the spot sizes seem to work on a V3-style head, yet look horribly blotchy on the body. I haven't got as far as the sub-surface scattering, but so far the fiddle of setting up the basic shader seems worthwhile. It'll be fairly easy to try it with another texturemap.

Mmmm, I'd need to see a render of the "blotchyness" to comment. If the texturemap is "non-human", then I'd say a few tweaks would be needed to get good results. Both the spots and sss use that fact that human skin already has some redness in it to get the results. If you use the script (or nodes) on a "green shimy skinned monster from the deap" - then I wouldn't have thought the results would be quite right! As a startingpoint - turn the spots off - if the blotches are still there - then it is something else.

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I've managed to reduce the blotchiness a lot -- I tweaked the Fresnel Spots when I realised it was the angled areas, such as the sides of the arms and head -- with hair, I was seeing the much smoother face area only. But you can still see a little of it. It may be that the Blinn node plugged into Alternate Specularity is having an effect too.

What I did was darken the spot colour, and shift it towards yellow (anti-Blue). That's made a big difference. No texturemap, I'm using a Simple Color node instead.

I wonder if average skin brightness is significant? Has anyone seen similar effects with African skin tones?

On the other paw, when I checked with texture-mapped figures, including the default human texture on Posette, I was getting the same effect. So it's not skin brightness. What did seem to make a difference was changing the Softness setting on the Fresnel Spot node. In the tutorial, the Softness is set to 0.00000 I adjusted the value to 0.5000 which matches the other Spot nodes. The blotchiness vanished, for all the skin tones I tried it on. I'm not saying that's the best value to use, but it seems to be the setting to tweak.

Interesting....Fresnel should be invisible to the eye (except on extreme close-ups). I suspect for the tutorial I used a high fresnel color value (RGB:114) - which is too much. For the revised RealSkinShader and HyperReal fresnel color defaults to around RBG:51 - so another approach to try.

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Thanks, that's certainly consistent with my experience. With the settings in the tutorial the spots were extremely obvious. Less intensity and some softening may well be the best answer. At least I'm getting some idea of how it all hangs together.

Here's a sample of the effects, using Sphere props. The top left is a reference. All the rest use the system given in the tutorial, **without** the emulation of sub-surface scattering. The Aiko Default is the basic skin setting used for the Aiko 3 figure from Daz; no shaders. The colour is used instead of a texturemap on the others.

Totorial default uses the settings from face_off's Real Skin tutorial, and shows the over prominent Fresnel effect.

The lower two spheres use the same shader tree, with adjustments to the Fresnel Spot node.

Note how the Fresnel Spots interact with the Specularity. It may be I need to reduce the specularity effect a little, and combine Softness with a slightly different Spot Colour.

Rendered with default Firefly settings -- no shadows, no raytracing, possibly a bit too much light.

Excellent comparison! From the look of those highlights - I wonder if the main light is too bright - and over-exposing the image (I generally have the main light at about 80% if there are 1 or 2 other lights in the scene). Should also use pure white light (is there a yellow tint to the light?). I wonder if the specular fidderence won't be so much with adjusted lighting? Great stuff.

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I gave it a try with one of the Radiosity Pro light sets, and that cut back the highlight a bit. Then, for this set, I eliminated the Alternate Specularity input. Otherwise, everything is the same.

Remember that the default Aiko has very little specular reflection. It does rather look as though specular reflections can easily burn out.

The Radiosity Pro sets use a lot of dim lights with one or two main lights.

I suspect the best result will come from a slightly darker Spot colour combined with some softness. Softness = 0.5 seems to lose the spot effect altogether, but the result looks too dark.

There's artistic judgement here. If you're going for a model-shoot look, I think that there needs to be more softness than for the housewife-next-door.

I agree, the softness at 0.5 one is a completely different color! Fresnel is implemented in the tutorial as a subtraction of color from the texturemap. The bottom right sphere has had a heap of color removed, and is darker than the rest - it has overpowered the texture. The sphere on the left has a much finer level of spots that have been removed - and won't impact the texturemap so much. The 3 spotted spheres also look like they still have some specular in them.

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Yep, I'll have to check where the specular is coming from. There's no actual texture in any of these, BTW. Just the same basic (and slightly approximate) skin-tone.