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why aren't renderers realistic?

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I've always been tormented by one question, why do renderers end up being unrealistic? Yes, there are renders that look similar to a photo, but when you look at a real photo, it is difficult to confuse it with computer graphics.
Is there a problem with the physics of light? Problem with textures? In AA filters? Is the problem in the elaboration of objects? . But even objects created using photometry do not look 100% realistic. 99.98% of the works are not given out by realism, and 0.02% are recognized if they are compared with reality. Where is the Achilles' heel and why is there still no render that would realistically be able to render an empty room without details and at the same time it looked like a photograph, even if it was just a white clean room?

For commercial work "good enough" is it. Those who seek better, know it only gets more expensive the more detail is added, so demands lower. 

Then, on creator's side, there just aren't many willing to take the path and, I also think while walking, observing, realizing more & more...
most ask same question....

Guess everyone has different priorities.

Once upon a time...

I think one of the problems are the shaders/materials. And I don't mean they are not programed well, or at least I don't think so. But a material + maps have tons of parameters. PBR made everything simple, but even those few parameters have a range of possibilities. And everything gets much more complicated when it comes to choosing good values for SSS.
For example the attached pics, a simple material for murky or muddy water. But I spent so many hours adjusting, and I'm still not sure it's completely right.

That's why when you mentioned that even objects copied with photogrammetry can look off. Because the shape is photorealistic, if it has enough details, but photogrammetry doesn't copy the shaders.

I'm going to ring the tone-mapping bell again.

Assuming everything "under the hood" is 95-100% physically accurate, light bouncing, materials e.t.c they can all be undone by bad tone-mapping. Think back to bad Vray renders of old with gross burnouts - the underlying GI simulation was still ok, but translating the dynamic range/colours as a DSLR/the human eye would wasn't up to scratch. I still believe it's one big area that overlooked in everyday CGI.

It also explains why even with a photo-scanned object, the rendered version in an good HDRI environment still won't look "right" in some cases. Another example; take a minimalist interior with next to no textures, different tone-mapping approaches can make the output look photoreal, and other implementations would make it look completely "fake".

Sure, tone mapping is important to make the image pretty, or to emulate the look of good cameras.

But what about bad photos ? Made with cheap cameras ? They still look realistic.

I did a quick search for these:


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