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Portrait - Eye material test
Posted: Tue Mar 18, 2014 8:22 pm
by birdovous
Still looking for some sort of a 'Silver Bullet' for making the eyes in DAZ Studio with the Octane Plugin...
This is my latest result so far...
Comments welcome

Re: Portrait - Eye material test
Posted: Fri Mar 21, 2014 3:00 am
by xxdanbrowne
It`s hard to see the eyes. Maybe a closeup.
Re: Portrait - Eye material test
Posted: Fri Mar 21, 2014 3:41 am
by tglaja
Close up pls.
Re: Portrait - Eye material test
Posted: Fri Mar 21, 2014 5:35 pm
by birdovous
Here is a closeup of the same material setting taken from a different scene. The only problem of this material combination is that the reflections on the cornea are still rather dull compared to those one gets by cheating and using diffuse material and a transparency map.

Re: Portrait - Eye material test
Posted: Fri Mar 21, 2014 8:05 pm
by xxdanbrowne
Maybe you need to use an HDR image or some other items in the scene.
Also maybe up the reflection.
I'm not an expert, however - my attempts look strictly amateurish. Maybe I'll take a look this weekend and see what I can come up with also.
Some others have gotten awesome results for eyes. Elbloko springs to mind as having gotten excellent results.
Also you might want to bear in mind the index of refraction of a cornea is 1.38
Re: Portrait - Eye material test
Posted: Fri Mar 21, 2014 8:28 pm
by birdovous
I'm using HDR image as source of light as well as mesh emitters. The cornea is a specular material and the reflectivity is set as high as possible. IOR is set to 1.38
It really looks that either I use my 'custom' eye replacement object that has tweaked UV mapping so the cornea is mapped to the same area of the texture file as the pupil and iris and then I can use glossy material for the cornea without having to modify the eye textures but then you have no way of adjusting pupil dilatation...
So it really looks that the only option for sharp reflections is to simply use the fake approach with the diffuse and opacity maps for cornea in combination with glossy surface for sclera.
Re: Portrait - Eye material test
Posted: Fri Mar 21, 2014 10:19 pm
by xxdanbrowne
Have you maybe done the same mistake as I did recently and have the normals flipped on the cornea mesh?
Re: Portrait - Eye material test
Posted: Fri Mar 21, 2014 11:54 pm
by ROUBAL
Hi, for what I can see, the eye model is too flat. The reflection doesn't seem to be distorted by the curve of the cornea. The cornea curvature (trunked sphere on the eyeball acting like a lens) is what gives a spark of life in an eye. It can be a glossy material, but is better if specular wit IOR around 1.45 like glass. It can be necessary to add some roughness (very few) to catch the light. Othewize you may not see this tiny light spot which gives life to the eye.
Also, I noticed that CG eyes provided with some softwares are often modelled with a concave iris : it is wrong ! The iris is convexe. It can at worse be modelled flat, but must'nt be concave, because it adds too much depth to the cornea and reduces the thin lens effect. Also, the iris (diffuse material) is not lit enough if modelled concave, and the eye may appear too dark, even in strong light condition.
Reference image on this page :
http://www.snv.jussieu.fr/vie/documents/oeil/
Re: Portrait - Eye material test
Posted: Sat Mar 22, 2014 1:40 am
by xxdanbrowne
Here's my attempt. I also couldn't get a very good surface glint.

Re: Portrait - Eye material test
Posted: Sat Mar 22, 2014 4:42 am
by ROUBAL
It looks like cut out of a flat drawing or a photo.
