Author Topic: MyLittleSomethingExperimental  (Read 11208 times)

2012-12-11, 14:06:06
Reply #30

Ludvik Koutny

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I have never experienced this kind of issue on a foliage rendering, mostly because i have set up foliage materials in a realistic manner. Non the less, i get unacceptable artifacts when rendering glass objects under direct sunlight. :(

2012-12-11, 14:18:47
Reply #31

lacilaci

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I have never experienced this kind of issue on a foliage rendering, mostly because i have set up foliage materials in a realistic manner. Non the less, i get unacceptable artifacts when rendering glass objects under direct sunlight. :(

Sure, I agree that my original setup was too reflective, not very real... I've fixed that but I have that scene right now at disposal so I'm trying stuff on the foliage with high reflectivity, so even if not real, it's good enough example to get that bug happening.

2012-12-11, 15:21:28
Reply #32

tomasd

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The one drawback of physically based renderer is that if you throw at it physically incorrect materials, it will blow up in your face.
The real pro solution is to yell at your modelers to get it correct (true story).

Glass under direct sunlight can be really really tricky with many internal reflections.

2012-12-11, 18:12:45
Reply #33

maru

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I know nothing about supersampling in Corona, don't know how it works, but in vray you have a setting that would probably fix issues with high contrast between pixels like in grass reflections - it's called "sub-pixel mapping" and basically it averages the colour value between X points BEFORE they get represented as a single pixel in output rendering.

2012-12-12, 06:33:49
Reply #34

tomasd

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Corona can do the same, and it definitely helps.

The other problem however is, that, as far as I understand the scene settings, flickering bright spots are actually correct.
If you have a lot of complex geometry (grass) that is highly reflective (mirror-like), then it is pretty much exactly the same as when you look at a road covered in broken glass on a bright day.
We don't have that many bright days now, but the ball season is coming, so maybe a better yet example would be a sequin dress like this:


Lot of tiny reflective surfaces, whenever anything moves it will flicker. And, thinking about the dress, I guess everyone will agree this is what should happen on it. Now if you model grass that (from distance) it looks pretty much like this, it will (and should) behave the same. Bottom line is, physical grass is not highly reflective, so neither should be its material in physically based renderer.
(I know it has been fixed, but I like the explanation with sequin dress, so there)
« Last Edit: 2012-12-13, 10:43:47 by tomasd »