Making an eyeball, hitting snags

Hey everyone, I’ve got a bit of a problem. I’ve been trying to put together a believable eye shader for a while, and I think I’ve got something. The issue is that the cornea seems to fade everything behind it to black instead of refracting the iris.
Here’s a render and my node set up.

All materials are set to receive transparent shadows, so that can’t be the issue.

These are the transparency settings for the cornea. I’m sure the issue lies here in some stupid error on my part. If anyone can nudge me along, that would be great.

For the other materials have you enabled them to receive transparent shadows ?

I–I just said…

Your texture node is mapping the color out completely in the Eye_whites node tree. It’s set to the iris portion of the eye to be transparent, then screening what looks like a black material on top of it? Do you have another material node setup for the eye under the cornea?

That black material is the eye specular/reflectivity. The iris uses a completely different material using the same texture. What I’m trying to do in this material is to use the mask texture to transition from the eye white material to the cornea material. I’m certain the black cornea is coming from some error I made before that specular mix, because when I remove the specular layer the cornea area is still black.

Hmmm, I’m not seeing anything wrong off the bat. Are the normals facing out on your cornea?

Yep. I’m starting to worry if this is a limitation in the renderer, which would really really suck.

can this be fused with my post before this?
Also, something stranger. When I add subsurface scattering to my eye whites layer, this happens.

Sorry about that double post, I wanted to edit the thing but it was being approved.

Have you tried making it so that all materials receive transparent shadows?


I’ve got another issue that I fear might might me in the ass down the road. I bumped into it when I was testing out possible solutions to this issue.

This one seems more rookieish, as I’m sure the solution is simple. All I did was take the alpha and apply it to the output. I didn’t expect it to alpha out the entire scene though.

It happens when I don’t render with alpha too. I’ve tried with both mask transparency and z transparency and it still masks out everything. I’m getting close to being at my wit’s end here.

Are there any alternative eye model/ material techniques that still allow me a smooth transition between the white and the cornea/ iris instead of a harsh cut?

Wow guys, really spot on and quick responses here. I’m really cherishing my new profile and I’m looking forward to the wealth of input on my future endeavors.

Yeah, that was sarcasm. Forgive me for the abrasive attitude, but I’m pissed. I made an account here specifically for help on this one issue and the first guy that responds didn’t even read the OP and he’s a mod. I excuse Kirby because he’s a friend of mine who got a laugh out of this thread and had to join in.

Well, I’ve gotten a work-around together, which is to have a separate mesh for the cornea, the whites, and the iris. I absolutely abhor the way it looks, but at least they look like eyes now.

I’m just missing that smooth transition I was going after. It looks like lego pieces for an eyeball slotted into each other instead of different consistencies of flesh fused and grown together. This solution will work for now, but I’m still looking for a real one.

Alright, so I’ve got a new problem that seems tied to one of the old ones. It seems Blender Internal just doesn’t handle multiple layers of refraction on top of each other. I think I’ve made a mistake, but idk.
I added “tear” geometry to simulate moisture pooled around the lower eyelid, and this happens.

ok, this is crazy. I turn on SSS for the eyeball, render the whole thing, and:

like, gimme a break. am I hitting that many limitations or am I making that many mistakes?

I’m getting the feeling that this is some extremely elaborate practical joke at my expense.

Hard to debug a setup like this without a blend, no joke

why are you going all out with nodes?
you need a cornea mesh and an eye mesh. the eye slightly smaller than the cornea. then you have your transparent material on your cornea with reflections and your eyeball material with sss on your eye. you dont need masks or fancy node setups, this is not cycles. make sure receive transparent is enabled on your eyeball