Eye and Hair in Iray Help Needed

Nathanomir

I finally have a computer that will let me work with Iray. Several issues cropped up yesterday that all y'all probably solved a year ago. They're eye and hair issues, and only show up when I use an HDRI map.

Here is the render that shows the issues the best:

The scene was lit with an HDRI -- Studio by Dimension Theory -- and a single mesh light. It was meant as an icon for a material preset, so nothing fancy. However, these issues show up in involved scenes as well. If it matters, the character is Devious Doll's Jenara for G3F, with Build-A-Babe skin. These issues have cropped up with other figures by other PAs, and with other skins.

1. The Eyes. They're cloudy. Her eyes are Awesome Eyes for G3F by Forbidden Whispers, number 28. They should be a deep, rich brown. All eye surfaces are set for Iray. Cornea is set to water-thin, with the bulge up to 100%. The only textures on any eye surfaces are the diffuse map itself, with nothing on the cornea. Now, if this cloudy look is just what happens when the IBL (or whatever the Iray term is) is used, I won't worry about it.

2. The Hair. Her hair is Mada by Goldtassel. You can see a dark band around her forehead. This happens with all my Goldtassel hairs, and Out of Touch, too. It doesn't happen with Emma and Jordi's hair, Free Spirit hair, or Kimberly hair. I already know the culprit. It's the gigantic skullcap Goldtassle (and OOT) uses. This happens in Reality, too, but it shows up as an outbreak of "geometrypox." I've tried adjusting the forehead and scalp, with some improvement, but not much. Turning the opacity of the scalp to 0 gets rid of the band, but also gives the poor girl bald spots. I know PBR systems don't much care for overlapping geometry, but I've seen plenty of renders with Mada, and other Goldtassel hair, that don't have this dark band.

Any ideas? Thank all y'all in advance.

Nathanomir

Update. Significat improvement with the eyes. I applied the diffuse map to the topcoat channel of iris, and they look better, but still cloudy. Applying it to the topcoat in sclera also killed that "glowing eye" effect.

Richard Haseltine

The hair issue may be helped by adjusting the Cutout opacity, it may be that the transparency map isn't quite black

AllenArt

Your eyes might be too bright because you are either rendering in the perspective camera or a camera that has the bright headlamp still turned on. You could also check the opacity map of the hair and make sure the gamma is set to 1.00.

Also you said the materials are set to Iray. Is the render engine set to Iray too?

Laurie

 

Nathanomir

Richard: AHA! I'll check that.

Laurie: DOH! I forgot to check the camera headlamp. That will probably do the trick.

I'll get back to you both.

Nathanomir

Well, phoo!

The camera headlamp is off, and the black in the transmaps is 0, 0, 0.

Nathanomir

Out of curiosity, I turned off the scalp transmap. The skullcap is definitely the problem.

AllenArt

Can I see your render settings tab? And did you check to make sure the skullcap transmap gamma was set to 1.00?

Nathanomir

Laurie: Sure. Which render settings tab would you like? I'll start with Environment, since that seems to be where the trouble lies.

Gamma, huh? Where do I find that?

Nathanomir

I don't know if this has anything to do with it, but the Base Mixing is inconsistent on the hair. Half are set to Metalicity/Roughness, while the other half are set to PBR Specular/Glossiness. Scalp is set to Metalicity/Roughness.

Toonces

I got the cap issue with sporty ponytail recently (OOT hair). Fixed it by setting smoothing to 5, collision to 7 and increasing adjust-headsize1 to 1%. 'Adjust-headsize1' is just one of many morphs included with the hair. It made the primary difference in fixing the issue. As I increased it from 0 to 1, I could see the issue disappear.

Nathanomir

Well ... I think you're on the right track, Havsm. But after playing with the sliders for Head Adjust, Forehead Adjust, and Scale, everything from +25% to -50%, and still not getting rid of the band, I think it's safe to say that Goldtassel hair does not work with HDRI maps. That isn't much of a problem, as they don't cast sharp enough shadows for my tastes.

Thanks for the help, y'all.

fastbike1

@Nathanomir  " I think it's safe to say that Goldtassel hair does not work with HDRI maps"

I think it's safe to say that your statement may be correct for your setup, but is an overstatement for the general case. It's not goldtassel's hair products

Here's my evidence.

Goldtassel's products are popular, yet compliants about this issue are few and the compliants are not limited goldtassel products. When these issues are tracked down, it's always some odd ocmbination of lighting and character placement in a given scene.

I never see these issues with goldtassel products (> three dozen) and I always have a HDRI as part of my lighting. Given your origianal statement "These issues have cropped up with other figures by other PAs, and with other skins.", I'd say it's your setup. Here's a quick example with Bobbity Bo hair and Dimension Theory's HDRI Light Probes Expansion 2. No other lighting.

Nathanomir

Hey, Fastbike. You're onto something. I turned off the mesh light, and the problem went away. Turned it back on and the band reappeared. So, somehow, the skullcap is reflecting (?) the mesh light. Okay, thanks man. This gives me something to work with. Lights I can move around at will.

Sorry if I sounded overgeneralized. That's from trying to use Goldtassel hair in Luxrender. Lux hates overlapping geometry, and the skullcap breaks out in "geometrypox," my way of describing what looks like a terrible black rash on her forehead. There is a way to get rid of it, and it's individual to each hair prop, but I've never been able to get the technique to work. Pity, because Goldtassel's hair is probably the best looking available. But if I can use his hair in Iray, and just move my lights ... whee!

Nathanomir

SON OF A ... !

Both problems solved, with one technique. I ... uh ... ahem ... didn't have my mesh light plane set as a two-sided light. The emissive face was pointed in the wrong direction. I'm going to go bang my head against the wall now.

Thank you all for your help. Sometimes knowing what isn't causing a problem is the best way to find out what is.