Making realistic eyeball for human character

raging_river

Hello guys, I am trying to create realistic eyeballs but I cant seem to get it look realistic enough, do you have any tips, or good tutorials I could take a look at?

TY

ZacD

Just the eyeball by itself, outside of the head? or an human eye being part of a face? Because there's some major differences in how you would do each one.

raging_river

Just the eyeball by itself, to get that level of reflectivity of the eye, the specularity needs to be done right, even after that, the colours still look really flat in Unreal. I just want to see other people's approaches to get me on the right road of justice. I've seen people split the anatomy of the eye into layers (as it ain't simply a round sphere), but this is not an effective route within a game engine, unless you use the shaders correctly

Sandro

Specularity alone won't cut it. You need to come up with reflection map as well, so that you still get those nice sharp highlights even when character does not receive direct lighting. You can use normalmap for shading iris and bumpoffset too if you really want to ramp up instruction count. As for colors, they don't really matter, as long as you have proper shadowing and highlights in place,

Also, bear in mind even if you have perfect eye shader, results will still look rather creepy if you don't nail their placement, scale, eyelids and stuff around them.

Bigjohn

It's true that in reality the iris area is concave. But personally I don't like building it like that. The reason is that the cornea adds a lot of refraction to it.



If you notice, even from that strong an angle (basically a side view) you can still quite clearly see the iris. It's super rare to see a shot of the eye where you can't see the iris fully. So mapping it to a spherical object ends up working pretty well.

Just my preference though.

ZacD

I believe most people like to model it concave because of how it catches the light, it adds a nice highlight that is on the opposite side of the specular, so it may look funky from extreme angles, but it may be worth it.

Ace-Angel

Parallax Map the Iris instead.

Gestalt

Don't make the sclera white, don't make the sclera too bright. The diffuse of the sclera should not be too much lighter or brighter than average Caucasian skin. Keep in mind that the eye also has sss so you don't want harsh shading. Make sure the specular isn't too intense, the specular should be pretty subtle or else you'll get a 'bug eyed' look.

JacqueChoi

wrote something a while ago

www.jacquechoi.com/ModellingRealtimeEyes.docx


not a great example, but the theory n stuff is there. (same as dustin brown)

Funky Bunnies

is this really the standard solution for realtime stuff? I always figured it'd be too much transparent stuff and layered geos

any examples of the games that have taken this approach? or some version of it

Mark Dygert

This is what I don't like about the indent approach...

To me this is way more distracting than any negative effects of having a convex iris. Like pointed out earlier this indent can be faked with a normal map, and even the bump in the cornea can be faked the same way too, sometimes using the same normal map just flipping the right channels to turn an inny into an outy.

Yea yea I know, eyeballs aren't technically round and the cornea sticks out a bit, but you know what? Round eyes are easier to rotate and keep from clipping through the eyelids when the character looks around. Nothing worse than a characters who's cornea pokes through their eyelids because some modeler wanted to be "anatomically correct".

erroldynamic

Hmm, some insightful info guys... and awesome write-up JacqueChoi, that's super helpful!

Mongrelman

The iris isn't actually concave though, a flat surface or slightly convex works and reduces that issue. But I do agree, that clipping bit is annoying.




I think we used to have a setup where we had a sphere for geometry, and two different normals maps. A convex for the diffuse and a concave for the specular. I didn't set the stuff up so didn't really get a good look at it, might be worth exploring. Not sure how you'd set that up though

Mark Dygert

dustinbrown wrote: »

Alternatively you could add one edge loop to the inside of the eyelid and scale it out a little.

That's one method but its not always easy to keep the eyelids out of the concave part when the eyes are moving around and the face is animating. It doesn't even need to penetrate the concave part of the iris just the outter more transparent sphere and suddenly something looks a little hinky. I still think its important to maintain those loops around the iris so you can control the pupil either through morphs or bone scale.

Bigjohn

See, the eyes in that ME2 shot look fake to me.


It's just extremely rare to be able to see the iris being concave in reality because of refraction, so we're not used to seeing it that way. And yeah, the clipping issue really adds to the problem too.

By the way, I've been geeking over this video for a week now:
[ame="http://www.youtube.com/watch?v=ergoh74N50Q"]Archeage CBT4 Character Creation - YouTube[/ame]

That's simply the best character customization system I ever seen. I haven't seen a single combination that looks bad. And the eyes are worth noting too.

MM

Mark Dygert wrote: »

Yea yea I know, eyeballs aren't technically round and the cornea sticks out a bit, but you know what? Round eyes are easier to rotate and keep from clipping through the eyelids when the character looks around. Nothing worse than a characters who's cornea pokes through their eyelids because some modeler wanted to be "anatomically correct".

it is actually quite easy to create an eye rig with corrective blend shapes to conform the eyelids to the cornea.

so if you can rig or have access to a tech artist who can help you with that then make a realistic eye with accurate shape. other wise just go with round eyes.

it all depends how far you wanna go.

Bigjohn

That's also assuming your engine can support blend shapes, right? Or is there some other way to export it (like with bones maybe)?

Zwebbie

Eh, you can only really tell the difference between a convex and concave eye from close-ups at an angle of at least 45° or so - not a common occurence in games, where characters are usually looked at from the front or from a slight angle. I don't think it's worth the trouble to make it anatomically correct if you need a more complex rig for it.

I'd like to draw more attention to the 'skirt' mentioned in Jacque's tutorial. They're easily forgotten or little known, but I think they're the foremost thing to make or break eyes. That Mass Effect shot doesn't have them, and I think the eyes look terribly out of place.

For what it's worth, here's a comparison of a pair of eyes I made a long while ago. First shot is just lit, second with specular, third with an AO skirt.

Gestalt

Cool! I've always found incorporating the eyes into the head one of the most challenging aspects of making eyes look right (they often have a 'bug-eyed' look in CG).

I never though of cheating the AO with a 'skirt', but that is seriously a great idea, and for me it's much more valuable in games than the double-layered/convex setup. If you want a shine in the iris there are ways to go about that in the shader, but for the most part what you see from a distance (how everything works together and the impression it gives) is what's really important.

Mongrelman

The skirt does indeed help a lot, had a go with that myself awhile ago. Also included a tear line for the lower eyelid in it with high spec which helps.

JacqueChoi

i flatten the iris, and just use a concave normal map.

in NEXT gen, we'll just model the entire socket properly.

benny350

Good thread about techniques here

http://www.cgfeedback.com/cgfeedback/showthread.php?t=263

JacqueChoi

^ ^

The problem with modelling concave eyeballs in videogames, is we don't model the inner eye socket like they do in films. We model it into a cone point, and generally let it intersect with the eyeball.

So what happens is, when characters look up or down, we see the iris clip with the inner eye socket.

ScudzAlmighty

I have to link this off the CGFeedback thread cause it's just neat
[ame="http://www.youtube.com/watch?v=ySMtB5nWxPs&feature=player_embedded"]Eyes in slow motion - YouTube[/ame]