Gregorius' Quest for Photo-Realistic Characters
Gregorius
Posts: 397
This is a spin-off of the "Photo-real characters. A different approach" thread in the Commons. A couple of people there have expressed concerns that I've been monopolizing the thread, and while not everyone seemed to mind, enough people did for me to feel it was time to start my own dedicated discussion. So this is my "Does this look like a photo?" thread, where I invite people to provide feedback on my renders as I strive towards photo-realism (defined here as something that could pass for a photo of a real living person for a majority of viewers). In my experience, there is much more subjectivity to it than one might expect. More than once, I've had some tell me I was very close and others tell me I still have a long way to go (in response to the same image, or at least the same textures/shaders and lighting). My focus, at least for now, is on textures/shaders. Please don't be afraid to be critical. I won't take it personally. Even if at times I seem a bit argumentative, it's most likely because I'm trying to weigh conflicting opinions against each other and/or want to make sure the problem isn't being mistakenly attributed to one thing when in fact it's actually something else. I think even my harshest critics will agree that I've improved substantially since my earlier work, and their critiques played no small part in that progress, so I can be convinced.
Here's some background info that might be helpful. I'm a relatively rare breed who uses Genesis 8 in Poser, not Daz Studio, so I'm dealing with the SuperFly render engine. I started with this merchant resource and attempted to enhance it according to both my own taste and some comments I've received over the course of development. One of the main things I've tried to do is generate diffuse and bump maps that truly contribute or at least emphasize different facets of the overall texture, rather than the latter just being a grayscale of the former, which I consider to be highly amateurish. This has led me in the past to create unusualy blurred diffuse maps, believing that the missing details would be restored by the bump map, which I think is really the only proper venue for them. I have in recent months retreated somewhat from this approach, realizing that such a rigid separation of pure color versus 3D micro-detail is an ideal that is simply not practical given my starting point. Currently, there is only a very slight blur on the diffuse map, and I've also revised my procedure for generating bump maps so that they're less uniform. Lately, the bump/displacement seems to be the one aspect on which comments have been most consistently positive. I have also devised a procedure to enhance the subtle hue variation in the skin maps, though perhaps not yet enough.
Perhaps uniquely, I also have the base figure rigged so that attributes like skin color, eye color, and hair color can be procedurally controlled via parameter dials. Finally, I use the same base skin, eye, and mouth maps for male and female characters. The only thing that changes between sexes are the masks that I use to apply facial hair (including eyebrows) and body hair.
To start things off, I leave you now with a close-up of my current best, with G8F as the Guinea pig. Please critique away. Tell me what you think I've got right, but especially tell me what you think I've got wrong.
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Comments
Wow. That's an amazing image! The skin is lifelike. So are the eyes. Impressive!
Looks improved, the skin looks more translucent but the eyes seems to lack that translucency and look somewhat glassy. The eyebrows look OK, but somewhat patchy as if she plucked them too much.
If I put my fingers up to the screen and block out the eyes I can say that the skin itself looks believeable to a good extent. It has some degree of softness from the SSS which I like. This merchant resource looks better on this young female that it does on an adult male.
Eyebrows are slightly more complicated than you have made them. While the strands near the center of the face tend to point upward what you will find nearer to the edge of the face is that the strands alng the top of the browk actually angle downward. Also, very rarely does the color of the strands vary as much as yours do here.
For the eyes to work you will need to find something not so different from the way you're implementing SSS on the skin. Without solving the SSS on the eyes, it will remain less believable than the skin.
As always, I admire your work and never give up!!
Thanks, everyone! Okay, let me tackle the eyes first, since they seem to be what commenters mostly agree on. Here's a comparison. On the left is an eye with the original SSS radius setting of 0.02 (same as in the above render), but on the right is exactly the same eye with the SSS radius set to 0.086 (same as the skin). To my eye, the latter looks like it takes it too far to the other extreme, but that may just be me. I know at least a few people seem to find it better if they can discern details like the veins in the sclera, and the higher SSS radius blurs things quite a bit. What do you think?
Honestly, Rashad, for the longest time, there was no color variation in the eyebrows at all, but they always looked flat to me in close-ups, even with some very mild anisotropic specularity. A while ago it occurred to me to try the same striated alternation of light and dark that's practically standard practice for head hair, and after some tinkering, that seemed to add at least some of the missing dimensionality to them.
Of course, the contrast between the light and dark striations has been toned down significantly since my first experiments with this technique. Currently, a grayscale map is used as the input to a bias node that operates on a simple base color. The grayscale alternates between hairs at 40% and 60% brightness (as a reference, 50% would just reproduce the unaltered base color). If others agree that the eyebrows look odd as they are, I could try a smaller range (maybe 45% to 55%).
Well to my eye the new eye looks better even without the vessel visibility. They aren't visible most of the time anyway. I think they need to be a bit more 'yellow-grey, the sclera, though.
Out of curiosity, what are your thoughts on this one? It's set to be exactly halfway between the two close-ups posted previously.
Looks like you've added a bit of veininess to the 2nd one above and maybe a bit of yellow-grey though not enough.
Greg,
I think the sclera looks much much better in the version where it has similar SSS to the skin. the version that is half/half is still an improvement over the original. The irises however still need a lot of work. they too need to have some degree of softness, and just like in real world physics, your scattering and absorption can cause blue shifting.
Now you need to try similar things with the iris. This will NOT be an easy thing to do, but if you can get it to work you'll see why it works.
As long as you are using 1990's era poser4/kozborough transmapped hair systems, your effort will fail the "photoreal" test immediately IMHO.
These "photorealism "aspiration threads always seem to focus mostly on tight portrait renders of mostly stiff ,lifeless young Ideal BMI ,white girls with zero environmental context.
That is fine of course if you are purely an indoor studio portrait artist.
However as soon as you pull the camera back
( and if she is clothed), any semblance of
"photorealism " quickly fades
A typical Daz conformer will be spotted straight away in the majority of cases.
A Dforce cloth will typically have Zero edge thickness, easily indentifying it as a 3D/CG cloth mesh simulation drape.
Composite an actual photo in ,as the background, and your
Daz CG figure becomes glaringly obvious in context.
Use an All CG/3D environment with Daz content and you still Fail as the attention to Detail on most Daz nonfigure prop content is frankly abysmal IMHO
Most can not even be bothered to bevel edges models with square geometry.
Imagine taking a person and completely immobilizing them
and placing a Black box over their head with one tiny pin hole
to see through.
Now place only the best sections of carefully curated images in front of the pin hole and and ask the person if it "looks real"
This is the Equivalent of what most people are attempting to do in these Many "photorealism" threads on the Daz forums
in My opinion.
Rashad, the SSS radius is already the same on the iris as on the sclera. Do you think it needs to be higher or lower? Also, the scatter color on one of the two layers of SSS on the eyes (including the iris) is already a pale blue. Do you think it should be less pale?
Wolf359, thanks for joining in! From my perspective, I think the focus on studio-portrait-style realism is due to a suspicion that, if we can get that right, anything more contextualized will be comparatively easy. This makes some sense in that studio portraits are typically lit and arranged in such a way that makes it especially hard to hide any flaws in the illusion, since the photographer is usually aiming for a very clear and lively view of the subject. Also, I would probably switch to more sophisticated hair methods in a heartbeat if the vendor support was there, but sadly, it's just not, at least not for Poser. Even for native Poser figures or natively Poser-compatible Daz figures, there are virtually no hair sets on the market for Poser's proper hair simulator, much less for a figure like G8F, which Daz never intended to work in Poser. I agree that we probably hamstring ourselves by sticking with trans-mapped hair, but most Poser-compatible vendors still haven't gotten that memo. For the moment, I just have to make the best of trans-mapped hair with high-quality mapping and some advanced shaders.
I'm still tinkering with the eyes, particularly the irises, but for now, I thought this was worth posting. It's an updated version of an earlier render, intended as a more naturalistic portrait, with the increased SSS on the eyes.
Gregorius I do like the eyes more in your most recent render. I do think you need to experiment with different light sets because it's difficult to see the flaws when you are always using the same perspective. It's like looking in to the mirror, but every time you look in the mirror you look from the same angle. You miss interpret, or don't pay attention to other aspects.
Also, I've got to say the hardest thing to do is be objective when you've looked at the same thing for so long. For instance, V7's eyes are almost twice as large as they should be, but if you work with the model long enough, the model starts to look normal. Try your shader on a different skin, or your skin on a different model and you will more readily see the problems.
Well, here's an even larger close-up of an experimental revision of my eye shaders. What do y'all think? Magnumdaz, I'll be posting a render with different lighting sometime in the next day or so.
sclera is OK but iris looks like a reduced resolution toon iris
Yeah, I kind of feel like I'm being pulled in different directions with regards to the iris. Rashad seems to think it needs more SSS, which of course will only blur it further, but you (Nonesuch00) and some actual photos I've seen suggest that the iris should actually look quite sharply detailed at such close range. I'll do a test render of a hopefully sharpened iris texture. In the meantime, here's a render of the same character with just a single light pointed straight at her, just to shake things up a bit and get at least a slightly different perspective as Magnumdaz suggested. I could also try some third-party character morphs to see how my textures/shaders look on different geometries than they've ever been tested on before.
Okay, this iris should look at least somewhat better, but I'll let you guys be the judges of that.
It does look better & the above at another angle and further away does too but still that close in on this render and the iris will look a bit more striated like muscle (that's what it is) but not muscle color. The striation is what causes this illusion up close of different shades of blue (and other colors).
Also the blue-green color you have would only happen at a distance, closeup it would be mostly blue with yellow, amber, or brown...depending on the person. That's the bigger problem.
By the way, I have been trying FaceGen to make Christopher Reeve and even with FaceGen it is hard to get a morph that looks alot like him. Also, one of the pictures I used make a huge cleft chin like you have so I was wrong I guess some people do have such a huge cleft.
I must say, I really like where you are going with this.
How's this for "a bit more striated like muscle"?
Better but it's still blue-green, I'd say the muscle part is very good now.
Nonesuch00, yeah, I think mapping the illusory aquamarine iris color directly may be somethingt we may have to live with, at least if I'm to maintain the kind of easy control over eye color that I consider too important to compromise. I may yet do some tinkering, though. Is a straight-up green eye actually green, or is it a similar illusion-at-a-distance? That'll help.
Anyway, here's another single-spotlight portrait, this time using a third-party morph that I don't think I've ever actually rendered before. This is Indira from EJ's Ethnic Beauties pack.
No what happens is absense of pigment is a blue eye and as the density of pigment in an area of the eye gets higher to area where pigment are goes from blue to yellow to orange (amber) to brown to very dark brown.
Green, Blue-Green, Hazel and those shades in-between are just varying mixtures of the of what happens in the 1st paragraph and illusions at a distance. The closest you'll see to a shade of green up close is hazel which is a green-brown color.
Actually I'm just going from people I know that I've seen their eyes. If you are going to make textures it is best you go to a more definitive source:
https://en.wikipedia.org/wiki/Eye_color
Although Wikipedia must be taken with many grains of salt often for something as dry a subject as eye color it should be OK but there are probably other sources you can use too if you searh.
Yeah, I might be able to do something with that. In the meantime, here's a return to a subject I haven't used in a while to see how she looks with the latest textures/shaders.
I've been busy! First of all, it's probably not a perfect imitation, but I've tried to at least roughly simulate how certain illusory eye colors are actually mixes of different colors that blend together into one at a sufficient distance.
Here's a straight-up blue eye.
And this is a straight-up green eye.
And this is a blue-green/aquamarine eye. The shader literally just blends the maps for the blue and green eye together at 50%.
Finally, I kept everything else the same in the preceding renders just for straightforward comparison to earlier irises, but I've also been experimenting with some enhanced SSS settings on the whole eye that might allow me to have the best of both worlds (clear blood vessels, but otherwise highly translucent). Plus, it's at least loosely based on what actually happens when light interacts with eye tissue. Basically, the scatter radius is now modulated by the amount of blue/cyan at the relevant point on the texture map, so that the blue/cyan component is scattered more liberally than others. This is the result. I rather like it, but what do you think?
Wow! Big improvement in realism.
Thanks! Just for the heck of it, I decided to test my settings on a hazel eye after adding a finishing touch or two. I moderately increased the SSS on the iris as Rashad suggested, because with the latest revisions, I thought it looked just a tad too crisp. I also finally figured out how to make my key and back/rim lights (both Poser area lights) appear circular instead of square. The latter was a minor lighting nitpick, but I figure'd I'd put it off long enough.
Now that looks like the colors are layered in thicknesses on seperate layers with is the correct look I think.
Here's a test of what the original sample portrait looks like with the new eye textures/shaders.
Looks better the eyes but too much reflection makes them look glassy. Also the veins in the sclera are a tad bit too heavy red and the way some of them flow doesn't look right but the iris made a big difference.
Thanks for the continued feedback, everyone! Taking a break from the focus on eyes for a moment, I decided to try a few more single-light portraits of some little-used morphs I have. I also decided to see how the new shaders look when applied to much darker skin and to freckled skin. These are some of the first renders involving some subtle adjustments to the skin shader as well.
First, we have EJ's Billie.
Next, we have EJ's Celine as a freckled redhead.
Finally, most of my renders of young women are very au naturale, since I've never been a fan of anything more than very subtle make-up. Just for the heck of it, though, here's what the same ginger Celine looks like with moderate make-up.