"next-gen" eyes
polycounter lvl 19
Wrote up a quick how-to for eyes using what I learned on the feature film I was working. Quite pleased with the results.
http://www.poopinmymouth.com/process/eyes/ng_eyes.htm
[ame="
http://www.youtube.com/watch?v=tq_OxhnILn8"] "next-gen" eyes[/ame]
Hit the link for the full writeup.
http://www.poopinmymouth.com/process/eyes/ng_eyes.htm
[ame="
http://www.youtube.com/watch?v=tq_OxhnILn8"] "next-gen" eyes[/ame]Hit the link for the full writeup.
Replies
If you want to write a nice shader that works in max and is easy to use, feel free and post it here. I want it. :-) Not quite sure what you mean about using a world aligned texture, because without parallax, you're not going to get the look of refraction where the highlight hits a "lens" while the iris is visible from the side.
Lol no, just texturing the eyebrows flat on the model, its not like eyebrows stick out 2 feet or anything, at most you would just have subtle bump in the lowpoly there. No need for transparency or anything like that.
Maybe for a pink-floyd game where you shave off your eyebrows?
And it's not 1 bit alpha, for whatever reason when using Xoliuls shader on my machine, soft alpha still makes the black areas slightly visible, so I have to enable clipping with a .1 cutoff. It does have a soft edge, but it's behaving wonky on this one shader for some reason.
- Why on earth did you model the pupil as a little pocket? It's 100% black, with no specularity, there's absolutely no way you can actually see the depth without wireframe being on. All it's doing is making your circular shapes wobbly.
- Eyelashes are, in my experience, more irregular, crossing and clustering. Reference.
- AO LAYER! There's no point making correct eyes if they don't appear to be in the eye socket. Here's a small comparison image of eyes I made the other day with and without an AO layer (FWIW, they're completely round eyes with no separate specularity layer) and Massbot explains them in his tutorial. He places the tear duct on the AO layer too, which I think might be a good idea to help that transition.
-Some people like to keep their lashes nice and organized
-I don't think X-shader allows for AO layering in shader format, which is the proper way to go about in this day and age.
How do the eyes you linked (tiny image btw) look from the side? It's pretty easy to get eyes that look good from dead on. Are you using parallax, or do they just fall apart from an angle. Do the irises on yours catch light on the bottom as well? That's why using either a separate indented iris works well, or some kind of in shader parallax.
You're right in that the pupil doesn't need to be extruded. I use geometry for it though so you can rig the verts to a bone that you can animate the scale on for pupil size changes.
The lashes are mostly straight because they can survive as clear delineated lines at a smaller texture resolution. More jaggy and overlapping can appear too clumpy or thick, especially for a guy. Ultimately it's a stylistic thing, this is just a technique that anyone can use with whatever eyelash style they want.
Also did you really need to be scathing? We're all here to (presumably) help each other.
It's a good tutorial, and I'm glad you shared. I wish more people would post their eye tutorials, because everyone seems to do them differently.
I'm sure we could jsut as easily shit on everyone else's methods as well.
The eyes I made don't really hold up from a side view, as you suspected. That was mostly a case of couldn't-be-bothered; game characters rarely show their faces up close from the side, and I wasn't sure how I'd deal with the gap that arises when the iris meets the eyelid. I believe Vig (edit: = Mark Dygert) mentioned in another thread that round eyeballs are just much easier on the riggers, because they don't have to take deformation into account.
Concerning the pupil, that's actually a very clever idea to have a variable size! That said... you could do that just as well with a flat pupil, couldn't you?
Anyway, my main point was really the AO. You've got nice eyes, but they don't look like they belong in the face because they're not getting darkened by a layer of brow ridge, eye lids and lashes, and that just looks... creepy, if you ask me.
They actually are being darkened, but the soft shadows from xoliuls shader are not very dark, nor do they do really tight fine detail. However they are shaded, and they do look much more floaty with shadows turned off.
A projected AO shadow is the way to go, and have worked with ones like that as long as five years ago, but with this particular setup, the AO shell would be penetrated by the lens geometry. So while I agree a proper darkening would work, it's something that would require a special shader, or foregoing the lens affect, which I think has a much better visual affect than the darkening fake does.
Also you'd be surprised how important this refraction effect is for the eyes to look good. Mapping on a standard sphere with no parallax effects is very "last gen" and doesn't look nearly as good. Even a floating white disc with a look at orientation to the light (for fake specular with no alpha), over top of a sphere with an indented iris looks better.
On further thought the upper eyelid follows the movement of the eye, so having the AO based on the actual texture of the eye itself (sort of baked on) rather than a floating layer, may actually work out if the eye is rigged well with the eyelids. You can't really do it for the lower lid (when you look up the lower lid doesn't follow as much as the upper lid does), but at the same time the effect is most noticeable under the upper anyway.
The biggest difference for me is when you view a face from a distance. If the eyes don't have the AO, and the right amount of shading, they look bright, bug-eyed and uncanny. Same if the specular is too intense (or they're constant floating white highlights...)
Yep, it's really a balance, because you can potentially have far too many layers of alpha. The ideal solution is alpha planes for eyelashes, and then a shader that uses parallax to indent the iris, outset the specular shine for the lens, and a projected AO all on one sphere. I've had that setup in-house before, but I am currently unable to figure out how to get it working in max that way, and I personally prioritize the specular layer over the AO, so I dropped it. I totally agree with you about overwhite eyes, though I find often that's just from artists making eyes "white" as in 255,255,255 rather than a tone very similar to the skin.
1) In general (not saying you do this), don't screw with the spheres original pivot point.
Once you edit the eye and make the shape non spherical it makes it hard to get the eyes to rotate properly. When I'm rigging I use the original pivot position to align eye bones as do a lot of animators and riggers.
"But I always reset xform on all of stuff and recenter pivot points after moving elements instead of objects! I'm a riggers best friend!"
Yea well in cases like this is makes another job harder.
1a) The work around for when modelers screw up the pivots:
Hopefully there is at least one vert left in its original position, so you can snap another sphere to it, then realign the pivot of your eye, to match the un-butchered sphere. Pain in the ass and totally avoidable, but works... if they didn't totally screw with the eye...
2) Anatomical correctness can be problematic.
The bulbous bulge in the cornea can easily clip into the eyelids and cause problems, especially once you start moving verts around in animation. Sure zoomed it when compared to an anatomy chart looks great but zoomed out at distance players notice the clipping a lot more.
The iris indent can be annoying and distracting to players, much more so than the lack of the indent.
2a) Sure you can put some extra geometry around the eyelids and double wall the eyelids but the eyes are pretty dense and that can be a lot of polys that will never be seen. If you're using a geosphere to save polys then you don't want to add a few loops to the inside of the eye socket to prevent the indent from being an issue like above.
2b) If you do double wall the eyelids can be difficult to weight if modelers are not careful about aligning the verts in the double wall. The inner wall could clip during animation. If they are aligned properly weights can be copied and pasted and the chances of the inner wall poking through drop, but don't go away...
2c) The chances that anyone will care about the iris indent, are pretty low. If it's really important, a normal map will probably fake it well enough without running into the above issue and there is probably already one applied to character's anyway so...
3) Trim those opacity planes a little tighter.
If the geometry is set to cast shadows you'll get big dark areas that do not represent what people are actually looking at. In the example above its causing an issue in the viewport. If it was trimmed tighter, the problem would still be there but not as noticeable and the father back you get the easier it becomes to live with.
3a) Opacity accurate shadows can be expensive and on something so small as eyelashes and eyebrows it's not worth it. If you have big opacity planes models get dark bushy eyebrows or dark circles.
3b) The double walled z fighting, issue pops up again. With something so tight and easily faked with a normal map, why add something as complex and troublesome as opacity planes? There is probably enough opacity in the hair on normal characters to make things slow down.
3c) A little extra geometry that culls problematic transparent pixels from the scene while helping to cast a more accurate shadow is a lot better than saving a few tris.
the problem starts right here, it isn't anatomical correct, its pretty much a fake to create depth to the iris, but it isn't indented
it is a simple trick to achieve said depth, or basically imitate how light scatters through the iris, it could be done with a shader as well, but as ben said, it's simple to create without any extra knowledge of shadercreation
i was trying to find the super closeup images i once had of the eye/iris, but i can't find it anymore
anyways her eis some crazy cool ref if you really want to go into detail of eye animation :P
[ame="
www.jacquechoi.com/ModellingRealtimeEyes.docx
The anatomy isn't necessarily "accurate", but at the same time Ben's technique emulates lens refraction, and how the lighting actually falls on an iris more accurately than a convex shape.
(pay attention to the specular on the lens, and how the lighting falls on the iris)
It's a standardized way to 'fake it' (as it's also been used for years by studios such as Pixar, ILM and WETA).
The indented iris isn't anatomically correct I guess, but the indent creates the problems I outlined. If you're going to have the indent then you need to think about how that will effect things.
Modelers sometimes get stuck looking at a model in one pose frozen in time and sometimes never think about what could happen when it moves. The more artists are aware of these issues the better the end result will be.
i do things a bit differently. i always add a cubemap to the eye to give it a wet feeling, and i always add a fake shadow under the lid. those two things really make the eye feel a bit more alive and set into the skull. i also exaggerate the thickness of the lid, so the read really well. here is a screen grab, my textures are not that high res, and it doesn't look too spectacular up close but i think it gets the job done from game distance, i focused on forms that would read well.
one problem I had with my last character was getting the spec to overlay on a transparant surface. but that might have been an issue with Marmoset.
Looks awesome Arsh. I see you built in more lighting into the eyeball as well, is the lighting of the iris just built in, right?
no i didn't paint in any lighting, but i did use a spec map on the iris, it just has low gloss. its nice to get that glint of spec when the light shines in the eye. it also has a very exaggerated normal map on the iris to make it appear really deep.
On the iris I'm asking how you're getting just the bottom to catch light. Is that vert indented? or is it flat with a normal sending it inward? Or is it you only have the spec map bright on the bottom of the iris?
Hope you keep the bakery idea going, it sounds really cool. There is something in a similar sort of vein here in the UK...I'll drop in the link in case you fancy a look.
http://www.graze.com/
for the iris, its an exaggerated normal map, the geo is flat. another trick to get them to pop and look really good in game is to use a slightly desaturated diffuse texture for the color of the iris, and a vivid specular color, this will give them a bit of twinkle. if you look where the light is hitting my iris its much more saturated that where it is not. this works well for colored eyes, like blue and green, and even is nice for brown if you pump the spec color toward orange.
i also used this technique for the lead character of resistance 3. here are some shots ingame from the engine.
Cool, thanks for 'splainin.
*edit* damn that looks good, face and eyes. :-)
So does anyone have any info on how to pull that projected AO thing off? Are there any examples of that in-use?
I was in the middle of getting one for GUN2 at neversoft, but the project got canceled and then I left before we got it working. I was just using a shell like Arshlevon's example in the meantime.
Also you can colour it reddish-brown so it multiplies more of a fleshier colour.
Similarly with the specular/reflection used on the outer shell. It's a LOT more efficient putting it into an additive blend mode.
The addition of both of these draw calls are very negligible as neither are sorting, or even being buffered in Z.
One final thing I think we all forgot to mention, was to remember to include some kin of SSS solution for the eye.
Multiply AO over total diffuse/total spec and control it via a constant.