Advice for human eyeball material in cycles?


As an exercise in Cycles rendering I’m trying to make a realistic human eyeball. Here is my first attempt, rendered at 2000 samples using CPU because of SSS.

I think the eye white would need to look a bit more wet, but I find it hard to add more reflection without making it look like plastic or metal.

Here is my cornea and white eyeball material, masked with a procedural gradient map (I learned this from the Gnomon tutorial on human eyeballs from Alex Alvarez). The iris is a separate mesh and material (simple with image, diffuse and a little displacement). Other than that, my world material has my own HDRi map for IBL.

Any advice? What else would you do to make it more realistic?

well done… nice :cool:

@aerosolsmell Thanks!

@blenderallday Thank you. Appreciate the feedback. I have looked at a lot of reference photos to figure out the transition from the iris to the sclera. I especially found these helpful: (Amazing macro shots!)

I have not been able to nail the iris/sclera transition yet, partly because of choice of modeling and texturing approach for the eye, but there is definitely room for improvement here. Any tips would be greatly appreciated :slight_smile:

At a normal viewing distance, the iris would never look as crisp and sharp as it does in my render above. Keep that in mind. The transition from iris to sclera would also look different at a smaller scale here (my eye model is about 25mm in diameter, but the camera is very close and the image size is larger than what you would see normally of an eye.

I have tried a lot of different approaches to modeling the eye too. Of the different models I have come across, I really like Alex Alvarez’s approach over at Gnomon Workshop. Simple and effective. Just need to figure out the shaders.

I looked at your link, and one mistake a lot of people seem to make, is making the sclera (eye white) glow too much, which Justin Holt points out in his Mari texturing tutorial over at Gnomon Workshop:

I learned quite a bit from Justin’s eye texturing advice. Unfortunately he didn’t go through creating any shaders (he used Arnold for rendering).

I found this thread quite helpful too. Great discussion and some really great work there:

{bukkit} / Lukáš is doing an amazing project, where he also goes into detail about how he made his eyes:

This page gives a hint to how important SSS would be for making the sclera look real in CG):

I also found these images quite helpful/interesting, for eye research:

I will keep on doing research, and maybe post a few more attempts once I figure out how to improve the shaders.

Here’s an other render after tweaking of shaders and geometry. The cornea now has thickness to improve the realism of refractions. I also adjusted the transition from the iris to the sclera a little bit.

Any other tips or suggestions?

The iris that you’ve made is about as good as anything I’ve seen.

The bump mapped veins makes the model look like one of those plastic painted organ models you see sitting on a shelf in a physicians office. When I look at my eye in the mirror, it appears to me that the veins are slightly beneath the surface and there is no hint of the veins catching specular highlights, they also look sort of squashed flat and a bit blurry at the edges.

Maybe for the transition, you could use an image texture as a mask. Start of with a crisp black and white image and blur it so you can use this to mix the two adjoining surfaces. With this method, you could use different masks with varied blur settings depending on how zoomed in you are.

@marc dion Thanks for the feedback! :slight_smile:

I agree about the bump mapped blood vessles/veins. I will change that.