I’ve been interested in studying anime style 3d models for a while now and I’ve noticed some interesting approaches:
Traditional Round Eyes
The most common among 3d characters. Perfectly round eyes mostly work for styles where the faces is close to realistic proportions (small eyes). This approach is what you want to try out first to see if it can fit the style you’re going after.
Art styles where characters have larger eyes in proportion to the face will have the problem of the eyes bulging from the face especially when looked on the sides and can clipping on the side of the face. You may need to adjust the face to compensate making it a bit tricky to pull off. You can also solve this by using modifiers like the Lattice or Mesh Deform to avoid clipping on the sides and lessen the bulging by flattening the eye for really stylized characters, works well within the animation software (Blender in this case), for games however I’m not sure.
For a strict anime look (large eyes) this may not be enough as a flat eye is the most preferable when viewed on the sides.
You could also make the iris hollow so that the eyes can interact with light sources.
Examples (enable wireframe display):
Flat
A very straight forward approach. The eyes are as flat as can be. For this to work however you need to maintain your character’s head to have a certain angle for it to feel 3d making it work on only specific styles (the “moe” styles is what I’d look to call them). I’m not sure how reliable this is when rigged and animated though.
Example (enable wireframe display):
Hollow Cornea with Iris only
This is an approach that really piqued my interest, this is where the “eyes” are only just a floating iris. Where the cornea (white part) part where the whole eyeball should be is just hollow. Easy to pull off, this also can be used on many types of character styles epecially exaggerated eyes while keeping a flat side view and maintaining the shape of the face while keeping a 3d feel.
The only drawback that I see from this is that you need a specific shader (something like an emission) for the cornea like an npr material, if not then the eye will be noticeably hollow when exposed to light.
Examples (enable wireframe display):
-this example has the iris pushed back further to make an effect where the eyes are following your, mostly used for a static work like this one
I’ve mostly seen these on models in sketchfab. Is it commonly used in games as well? AI Kizuna’s rig seems to use this type of style.
EDIT: After rummaging around the net it’s actually used in Guilty Gear Xrd, the shadow casted (top part of the eye) from the hollow cornea can add some additional depth
If you’ve got additional insights please share! 