I just ordered pp2014, upgradingfrom pp2010.  I just watched the sm webinar covering sss, butthey didm't cover eyes.  Iwould like to know how to make good sss eyes in 2014.

Thanks in advance.

Boni

1. Use SnarlyGribbly's EZ-Skin 

2. I'm not convinced SSS on eyes is needed for anything other than close-ups

Agreed, but I am looking for instructions, rather than a prepackaged product.  Any tutorials out there?

Eyes are special.

The eyeball, the iris, the pupil, the cornea, all need to be looked into, and all attribute to the final result, and some will certainly interfere with each other.
Do all need SSS?

Be certain to put them all in different SSS groups or you can get some nasty blue artifacts.
Have not seen a tut on the subject yet.

I think BB had en eye setup on his site. You could check there and build from there on?

I have not posted an eye setup on my site.

I have in various threads, but I have problems with a generic solution.

1. Different figures have wildly different arrangements. (Eyesurface that overlaps everything and includes cornea, eyesurface that overlaps everything as well as a separate cornea surface, no eyesurface just a cornea, etc.)

2. The luminance level on the sclera is wildly different on one texture set versus another, so tuning to match what real eyes look like is always an exercise on your part which requires that you fully understand how to build and tune a shader.

3. People differ on whether they intend to go for max realism or they just want quick and dirty and they're willing or even enthusiastic to use textures with burned-in highlights. These look incredibly stupid when you use scatter and real reflections.

4. People do not pay attention to the environmental factors - your light source(s) had better be tuned for realism (use my light meter first) and if you want good looking reflections based on realistic reflection values (Fresnel!), you need HDRI imaging or real props that glow at HDR levels. (Much greater than 1)

5. Poser transparency lets light through a cornea/surface onto the iris. Poser refraction does not. Realism requires refraction. Therefore you get little or no light on the iris. Compensations require understanding how to self-light the iris just enough to deal with this. Or require crafting a cornea as a separate actor (as I did with the BB eye) so that you can turn off shadow casting on from the cornea.

Wow, this is exactly what I'm looking for.  I do understand some of the challenges involved ... but believe that the result would be worth it.  Primarily I will be workingiwth V4 ... but knowing that I'd have to approach different figures differently helps a lot. 

After reading over your list BB, (may I call you BB?) I was caught by the problem of Transparency and refraction ... and self illumination for the iris.  Since I'm upgrading from PP2010 to PP2014 I haven't had the pleasure of working with self illumination yet.  Would this be a workable solution if worked with subtly? 

Also since the environment plays such a strong factor in this ... finding a "master" shading system for each figure to use in well orginized scenes, using good environmental spheres such as yours could be counter productive?  That is each shader must be created to fit a particular scene ... or could a master be made that could be used in any scene as long as the scene is set up well? 

Vilters: you have braught up some good questions too.  I'm definately bookmarking this thread! 

Boni

in re: 4, didn't they fix refraction shadow-casting yet?

Quote - in re: 4, didn't they fix refraction shadow-casting yet?

No and I reopened the bug report on the bend angle - turns out it isn't done right.

also in re: 4, have noticed reflected scenes usually too dark, and apparently it isn't user error.

I have another question.  Why is it with most poser renders that the shadow of the lid and lashes never come down over the upper portion of the eye as it does in "real life"? It's an effect I've tried to figure out for a long time. 

Thanks

Boni

they may use shadow-mapped lites, low pixel samples or high shading rate.  they may also turn off shadows, like they do for transmapped hair.

Sorry I was gone so long. I am in the middle of developing VSS Pro and I wanted to use it while working on these settings, since it is so much easier to make multi-material changes with a single click in VSS.

So I have done some experiments and I'll show you some techniques on how to set up eye shaders on V4.

First - sun and sky (one infinite light, cloudy sky EnvSphere).

The cornea (seen here in magenta) covers only the iris.

My suggestions:

1. Use the Cornea and Sclera to make reflections. Make the EyeSurface invisible.

2. Use the EyeSurface to make reflections. Make the Cornea invisible.

Option 1 gives the best results as you can apply procedural bump to the sclera and refraction to the cornea and get a very realistic looking eye. But you only notice the incremental benefit up close, and there are some gotchas to it that make it more work.

Option 2 is less work and gives good results. I did option 2 in all those images, so it's pretty good.

So - either way you need to make something invisible. This is the shader to do it.

It is 100% transparent in all directions.

BB, looks promising, but...

in photography, one usually sets the camera focus to the eye(s), so these are "tack sharp" in any image whatever the camera DoF set.

But in the images above, the facial skin appears quite sharp while the eyes make a blurred and watered impression to me. I see a difference, in my opinion it's too much, and the wrong way around. She seems just to start/stop crying to me.

Hope this gets improved upon.

The Reflect node gives us reflections from objects. (including the EnvSphere)

The Blinn node gives us reflections from Poser lights. Lights are a fiction - they're not really there. They have no size. 

The Blinn eccentricity affects the apparent size of the light source as well as the apparent blurriness of the object. It has to be matched to the Reflect node's softness. But not literally matched - the two values have very different interpretations.

In my shader work, I express the "blur" of a surface with the word "blur". Blur can be 0, .1, .5, .75737, 1, 1.5, 2, 5, etc. Above 5, Poser's Reflect node softness really breaks down and doesn't work, so watch out for that.

To translate blur to Reflect and Blinn nodes, I use the following rules:

Reflect.softness = blur <--- that was easy!

Blinn.eccentricity = .03 + .065 * blur 

In this shader, I used a blur of .1, and so that is how the values got there.

The Blinn node also has its own built-in sort-of Fresnel effect (SpecularRollOff), which I turn off (set to 1 = no falloff) because I intend to always modulate reflections with a Fresnel_Blend node.

The Blinn Reflectivity controls its brightness. This is a "relative" term. If you try to understand this Reflectivity deeply, you will probably fail and we'll have to have a very long conversation about this one parameter and how Poser's unitless light system is kind of a pain.

Short answer, is I use this formula

Blinn.Reflectivity = 90 * (.5 ** blur)

That's 1/2 raised to a number equal to my chosen blur. In this case, with blur = .1, that comes to 83.973. (I did not type this - VSS built it.)

The Reflect Quality parameter is very fussy to deal with. As a rule of thumb, for curved things it can be under .5 with moderate blur. If your blur is 0, it can be .1. VSS generates appropriate values based on the blur. For eyes which really don't need blur at all, you could speed them up by removing the blur (blur = 0) and set the Quality to .1.

I don't want to talk about RayBias. It's complicated. I left it at its default for now.

Quote - But in the images above, the facial skin appears quite sharp while the eyes make a blurred and watered impression to me. I see a difference, in my opinion it's too much, and the wrong way around. She seems just to start/stop crying to me.

Hope this gets improved upon.

Are you talking about the iris and sclera texture (color maps) or the reflections?

The color maps are a little blurry in and of themselves, and then the Scatter node smears them some more. This is adjustable. I didn't attend to it.

But I don't know if that's what you're referring to.

thx fr great eye discussion!  they don't look blurry on my monitor.

This is with the blur set to .1. The reflections look sharp to me.

I don't use blur = 0 very often, because I like to use pretty crappy min shading rate for speed, and so you sometimes see jaggies in reflections. By softening reflections a bit, those jaggies go away. This saves me having to use costly low MSR for the whole scene.

A blur of .1 is not enough to smear reflections on a curved surface - but just enough to hide pixellation artifacts.

Now, being that we're up close here, the unnatural smoothness of the sclera is revealed. A closeup requires that you no use EyeSurface, but rather you set up cornea and sclera for the reflections. We'll get to that later.

If you don't like the tear at all (many people don't) then use the invisible shader on it instead. 

For artistic reasons, I increased the IOR to 1.4 - this gives slightly more obvious reflections without being ridiculous. The actual IOR of water is 1.33. I assume tears are close to that, but perhaps salt increases the IOR? In which case, my 1.4 is probably dead on.

We also possibly have a thin-film effect bouncing light between cornea and water surface, which may increase the reflection amount. So it's sensible to go higher if you like.

If you love glassy shiny eyes, go way higher - try 1.5 or 1.6. (Glass is 1.54) If you go above 1.6 it looks crazy like silicon eyes. Don't do that.

The way this is working is that the Fresnel_Blend node gives us a proportion for how much light is reflected. The complement of that is refracted. It turns out that when you plug something into Transparency, the value is assumed to be an opacity which is multiplied with other things - in particular with Alternate_Diffuse. The complement of what is plugged in is transmitted. 

Voila !

Note: My node names are sometimes adding or removing _ - this is because VSS generated them. Learn your nodes and the _ will never bother your understanding.

It's basically color map -> scatter.

However, I like to adjust. I always enjoy having an HSV node after my color map so I can tweak. Here I tinted it yellow (because I felt the color map was too blue). I also made it brighter (Value = 1.5). You can adjust saturation as well, but I didn't need to here.

I also have an HSV after the scatter. This is because I found it best to boost the input to scatter and then suppress the output. I can't tell you why this helps, but it does. I generally leave that .8 Value no matter what.

So the chain is color map -> HSV -> scatter -> HSV.

The bump part is optional. The texture set I loaded had a bump map here. If you're going to use the bump map, do it right. 

1. Make it linear - set its gamma = 1

2. Subtract .5 so that gray is "no change". 

However - the node values here are NOT the same. I wanted the somewhat weak blue iris texture to be more exciting. So I boosted both saturation and value. And I didn't need the yellow tint.

I forgot to mention earlier - your eye scatters need to be in a different scatter group than your skin scatter. Assuming your skin is group 1, set the eye scatters to 2 as I've done here.

If you don't remember to make a different scatter group, then the skin will look blue around the eyeballs.

1. Use the "invisible" shader on EyeSurface

2. Use the "smooth reflection" shader on Cornea.

3. Use this on Sclera.

This shader is basically BBGlossy in modern form using all the features of the current Poser.

Note: This bump map is crap. First of all it's derived from the color map, so the dark arteries become indentations. I had to invert the bump value to -.03 inches to flip the depressions into ridges. You probably want to use a good bump map and won't need to flip the sign on the bump. Or - perhaps we should (as I so often do) discard the bump map and use a procedural bump. Hmmm - I will try that in a bit.

I actually increased the maximum value on the morphs and used 2. 

Here they are set to 1.

The morphs are:

EyeCorneaBulge

EyeIrisConvexity

Here's the refracting cornea material.

This requires you to decide how much to light them.

In the shader, you grab the HSV coming off the color map and plug it into Ambiet_Color. Set the Ambient_Value as you like. I used .5 here.

Enjoy!

Show me your work.

(Note: I saw after posting this that I had her neck twisted in a weird pose - ignore that please.)

With the refracting cornea, you can run into one of Poser's weird problems. The ray bias will allow you to skip the iris. Any surface that is closer than the ray bias distance is ignored by the refract or reflect nodes. 

On some figures you can't make this go away. Others you can adjust (decrease) the refract ray bias and make it work.

I thought the ring around the cornea here was the ray bias but it's actually because I changed the head angle. Now the lighting is different and the iris glow is too strong.

That's why you do not want to use glow. It's a pain in the butt.

Quote - I gave it a whirl.

I like it!

Something I noticed - the sclera has an obvious symmetrical red spot below and outside the iris, and the left and right iris appear identical too. Did you make the texture? If so, mix those up a little.

If you bought it - then tell the vendor not to be so lazy. Draw two eyes.

In the meantime, let me come back to my statement that "in the render, the eyes made a weaker (less sharp, ...) impression that the facial skin" or something alike.

So I made a comparison with some photographs from the galleries - BBs render is in the middle. Postwork on all: rotation to set the eyes horizontally, scaling to align the pupils amongst all images, slight levels adjustment so all have the same black/white points.

My impression:

1. in all photographs and render as well, the eyes have about the same graphical quality.
   So since this thread is about eyes: they are good !!
2. but in the render, the skin is somewhat darker, sharper, and more detailed while in all photographs the skin - in colorvariation like freckles as well as structure variation (bump/displacement) - appears brighter and far less detailed. This seems to be due to a difference in lighting (much stronger, broad flashy in the photographs) and a stronger response of the skin to that light (more specular / reflective / scatter than in the render).

So the relative difference between eyes and skin as I flagged earlier still stands, but it's not in the eyes but in the skin instead, and IMO that's something to bear in mind when overall photorealsm is of interest.

Homework!  :wub:

using pp12, though.

Well you showed a bunch of glamour photos which look like they involve makeup, postwork blemish removal, and extra bright lighting. I rendered the freckled uncovered skin of an Irish woman in natural light (mostly).

But I can change it quite a bit while still using the same textures and same node setup - just different numbers. There's a lot you can do with shaders and lighting.

Honestly, I suspect the real issue at this point is that the eye texture itself is just slightly less than believable and it's throwing off the realism.

Quote - Honestly, I suspect the real issue at this point is that the eye texture itself is just slightly less than believable and it's throwing off the realism.

I think there is a lot of truth in that and the pictures ealier were not only glamour shoots but also not high quality and a couple look as though soft focus was used.  I can see the point trying to be made here but not sure on the strength of the examples.

The other point is that the OP was looking for the best SSS technique for eyes and, having followed this thread and played with my favorite character this has to be the best setup I have seen for believeable reflections.  I am still playing with the parameters as I like the eyes to be a little sharper than I have at present.  This may also be a factor of the texture but lets be honest here, this is a long way from the eyes currently suppled with many characters.  I mean finding a character with the option for real reflections is a bonus, most I have seen come with reflections burnt in making the textures a complete non strater in this context.

These are the standard texture maps, but obviously I replaced the shaders.

The morphs are mostly the built-in dials. I had to do a nose job using a magnet, since no suitable morph would make the middle part narrower.

The forum is slightly shrinking the image. Click for full size to see the detail.

she's irish?  it looks like pepper potts.  looks great with hair!

Wow, love the render of Alyson2.

Well this is my attempt.  Reflection is mainly the lighting of the room which has light panels in the ceiling and lower part of the walls but there is also some reflection from a display panel as well.