OTOY Forums

Hi Everyone, a few weeks ago, I decided to create a new set of eyes for one of my personal project. It needed to look good under any lighting conditions and be easy to customize and reuse.


The color of the iris is changeable in several ways using a single gradient. The colors of the gradients are passed on to several shaders mixed to achieve the effect.


The shade of the iris and its central corona are controlled independently for a wide range of variations.


Nice green eyes. Dimensions are accurate. All IOR used are from physical measurements. Some of those renders could have used more convergence time, sorry for the noise.


Scary lighting or something. Whatever. To achieve the full translucent effect on the sclera, I modeled the choroid connective tissues inside the eye.


This is pretty much where the illusion breaks. I could use a higher resolution model but this eye is supposed to be shared across multiple characters and I want it to be fairly cheap to save memory. Ideally, I would increase the level of details with displacement. Note the dichromic iris and its reflection in the lens.


Closer to the lens behind the iris. Here, it is showing signs of cataract. Unfortunately, Octane's procedural noises reach their maximal scale limit.


Retina you say? Of course. Flash!

Very nice!

Thanks a lot man!

I guess I should give a bit more details.

Inside the eyeball are several models to achieve the effect. Most notably the choroid tissues.


The eye stripped of the sclera and conjunctiva. The shiny blue part is the choroid I was talking about.


Straight inside the eye, cornea iris and lens removed. You can see the retina at the back.


Everything is here but the choroid connective tissues seen above have been removed. Notice how the light goes through the scleral envelope now.


The full model. See how the choroid acts as a black chamber and affects the periphery of the iris.

Octane is so much fun. All critiques are welcome.

This is probably the most realistic and anatomically accurate eye I've ever seen.
I would like to know more about how it's constructed, as I make human characters in my daily work.
Can you show me a breakdown of this?

It is quite amazing!

Hey guys, thank you for the compliments.

In fact, it is very simple. It just imitates life a bit... up to a certain point.

Here is a quick breakdown of the geometry. It is of course highly simplified. I have tried modeling further elements, notably the aqueous and vitreous bodies or the variable IORs of the lens . Unfortunately I had to give up on this level of detail because I couldn't figure out how Octane functions with different IOR objects nested within each other. The results were very unpredictable.



Can somebody explain how Octane copes with traversing materials with different refraction indices?

hi, wow, impressive
about the liquids with different ior, the solution is to work with sheets and avoid solid surface compenetration. in octane, a ray maintain his ior until hit another surface with a different ior. look at the second example in this post:
http://render.otoy.com/forum/viewtopic. ... quid#p6577
ciao beppe

Thank you That's pretty much how I tried to model the surfaces inside. It's easy for a glass of whisky but it gets more complex with the inside of an eye. The light has to go through the cornea, then the aqueous humor, then the lens, then the vitreous humor to finally hit the retina. Describing those different bodies inside using the rules you pointed to is a bit of a mind bender.

I will try again though, just for the sake of it, because I'm honestly not sure it would add anything to the end result. The different refraction indices inside are all fairly similar in the end.

Question though, when the light crosses multiple adjacent surfaces with the same IOR, does its trajectory stay the same or does it get increasingly deviated at each surface hit?

El-B,

Thanks for this post. This is the ONLY way to model realistic CG eyes IMHO.

Of course, yours are the most accurate and detailed I've ever seen. I don't believe I've ever seen one with a functioning retina! Great work.

best,
O

Sorry, one more thing,

This is a great link for refences:
http://www.surenmanvelyan.com/eyes/

best,
O