12

For a realistic Iris, you need: Geometry: Irides are very different for different people and their appearance changes drastically depending on whether the pupil is dilated (sphicter muscle relaxed) or not. You will not get anywhere with primitives only. The whole structure is like a thick stretchy wrinkly cloth suspended in water. Wrinkles appear and ...


9

Path tracing is the standard technique in non-realtime photorealistic rendering, and you should look specifically into bidirectional path tracing to get effects like caustics, which you can't really get with basic path tracing. Bidirectional path tracing also converges faster to the ground truth as shown in the below image: Also Metropolis light transport (...


7

Few things, but usually this is what it takes to make the difference: 1- the material reflection at his head, he is bald, yet the diffuse texture shows color difference where the hair is, this means he has a shaved head, not a natural bald, this should translate in reflection, take a look at his head, top right (top left for the image), the reflection is ...


6

I don't know if this is exactly what you're looking for. I work tangentially in the film and TV industry. I don't work for a studio, but I work on the software that studios use for their productions. It's software that any user could buy if they wanted to, but it has been used in feature films, television shows, commercials, music videos, and more. About ...


6

You probably know that the BRDF is to calculate the reflected light, from a light source to a camera (In examples a light source and a camera is used, but it does not need to be just that). The property that you are talking about, basically says that when you swap the light source with the camera, it still gives the same result. Lets look at an example I ...


5

For offline rendering, caustics and dispersion effects (different colors of light separating, as in a prism) are usually calculated using some form of photon mapping. That's a fairly expensive technique, even by the standards of offline rendering, and it falls more under the "physical simulation" side of things. If you're looking for more approximate ...


5

One of the big ones is the use of constructive solid geometry rather than triangle meshes. Ray-triangle intersections are faster than almost any other ray-shape intersection, but it takes huge numbers of triangles to approximate the surface of a cylinder or torus, not to mention some of the really exotic shapes such as julia fractals or generalized ...


4

I think you identified the problem yourself in your question : it still definitely looks like a 3d model It's obviously hard to tell and subjective, but while many things are off in this picture, the expression and the proportions of the character model are what I find most unrealistic. It is to the appreciation of the art director, but most of the time, ...


4

Hard to say because we can not see the code. Subsurface scattering might be part of that equation. I would just point out that human brains are extremely specialized in facial recognition. It has been postulated that the brain has a inbuilt defence mechanism to detect alien impostors/anomalous people. You are right in middle of what is known as uncanny ...


4

Two big ones you're missing: Angle-dependent reflection. This is one possible cause of your "transparent in places and not in others" effect, and the most likely cause of the missing wetness. Ice cubes usually have air bubbles trapped inside. This shows up as a white volumetric haze denser in the center of the cube (for small bubbles) or distinct bubbles (...


4

I've found that bump mapping when calculating lighting and refraction rays can add a lot to the look of ice. It makes the ice look textured and imperfect, like a melting ice cube would look. I sort of wonder if maybe animating a bump map could help make it look wet, as water sheets / droplets ran down it's surface. The images below look pretty nice, but ...


3

According to Wikipedia, ice has a slightly lower IOR than non-frozen water, though I don't know how much that difference would affect the results. The "opaque"-looking parts of an ice cube are caused by clusters of microscopic bubbles formed during freezing. You might be able to model those using geometry, but given the scale and number I suspect that some ...


3

I suspect the answer to (a) is simply performance. Full volumetric path tracing / photon mapping based on the RTE can certainly be done (and I'm sure it sometimes is), but it's very expensive and requires enormous numbers of samples to converge to a noise-free result. This is especially true when the scattering medium is very dense, like in human skin and ...


3

Even though I didn't know about monte carlo path tracing when I wrote this, I accidentally described it. Ironically, monte carlo path tracing is the answer I was looking for at the time. Naive monte carlo path tracing works by evaluating something called the rendering equation to numerically solve the color value of a pixel. It takes random samples by ...


2

I see several things that are off in addition to what others have said. He doesn't appear to be breathing. He's in a very cold place (it appears to be snowing), yet there's no breath in front of his nose or mouth. It's snowing, but none of the snow is in front of him. It's all behind him, or on his clothes, but not falling around him. I feel like our brains ...


2

The closest thing I know of to the "computer: enhance!" trope in real life is the family of Single Image Super-Resolution techniques. That page shows a number of examples of the results on various images. You can see that while it improves the visual quality of the enlarged images, it's a long way from what you see on TV where they can read the text on a ...


1

The most common way I saw is to have photons of several different wavelengths. One then renders with each wavelength and blends the results into the final image. "Existing work": Psychopath Renderer and The Secret Life of Photons.


1

One hacky method I've seen in real time raytracers / ray marching is to cast a ray per color channel (rgb) and do things Iike have different refraction indices per color channel.


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