Updated principled shader

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lacilaci
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Updated principled shader

Post by lacilaci » Wed Dec 25, 2019 3:24 pm

Any word on the addet transmitance features for disney?
Even with latest shadow tricks, proper volume for liquids on glass gets super dark unless liquid is "architectural"(and even then it's affected by glass, see attached images). Some cheap sss in disney could be useful for these (and for skin, etc..)

here:
A.jpg
B.jpg
shadows are disabled (set to white, in both) yet volume always struggles to get some proper lighting. I assume this is correct behaviour and I simply need fake/simple sss as in cycles or wait forever and use caustics maybe...?

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lacilaci
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Re: Updated principled shader

Post by lacilaci » Wed Dec 25, 2019 3:52 pm

Volume on it's own kinda works, but it has to have null as material (so just volume is used)
The moment any glass is introduced it goes dark...
B1.jpg
A1.jpg

Fox
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Re: Updated principled shader

Post by Fox » Thu Dec 26, 2019 2:59 am

With rough glass it's not dark, but you still need GPU or 2.

Here 10 min on older cpu, this should be 1 min on gpu.
HybridBackForwardPhotonGi
10min noisy.png
2.81a Blend
juice2_Fox.7z
(1.81 MiB) Downloaded 13 times

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lacilaci
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Re: Updated principled shader

Post by lacilaci » Thu Dec 26, 2019 8:09 am

Fox wrote:
Thu Dec 26, 2019 2:59 am
With rough glass it's not dark, but you still need GPU or 2.

Here 10 min on older cpu, this should be 1 min on gpu.
HybridBackForwardPhotonGi
10min noisy.png

2.81a Blend
juice2_Fox.7z
hm.. rough glass kinda helps if I disable glass shadows completely... but without any shadow at all it kinda looks weird in scene

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lacilaci
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Re: Updated principled shader

Post by lacilaci » Thu Dec 26, 2019 8:41 am

Aaand no, not good enough...
I really hope that principled shader sss will make this doable

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Sharlybg
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Re: Updated principled shader

Post by Sharlybg » Thu Dec 26, 2019 8:43 am

lacilaci wrote:
Thu Dec 26, 2019 8:41 am
Aaand no, not good enough...
I really hope that principled shader sss will make this doable
Wonder how renderer like Octane and cycles results look like in this specific case ?
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lacilaci
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Re: Updated principled shader

Post by lacilaci » Thu Dec 26, 2019 9:14 am

Sharlybg wrote:
Thu Dec 26, 2019 8:43 am
lacilaci wrote:
Thu Dec 26, 2019 8:41 am
Aaand no, not good enough...
I really hope that principled shader sss will make this doable
Wonder how renderer like Octane and cycles results look like in this specific case ?
Well it's difficult to produce good looking juice in general, this is why some added flexibility is needed.
First, some basic sss materials should be very easy to set up (how disney allows or what corona does) and then as more rough it gets, or more scattering is happening it should be compensating somehow for the darkening.

For example even rough glass gets very dark the more rough it gets, if you look at principled shader in cycles the use of multiscattered ggx will always keep the glass bright. Maybe something similar is happening with volumes in luxcore cause the more scattering the volume gets the darker it gets (maybe physically correct but looks unusable mostly)

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lacilaci
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Re: Updated principled shader

Post by lacilaci » Wed Jan 01, 2020 9:54 am

I can kinda get it correct looking when making the juice smaller...
it only get's darker when juice mesh penetrates glass mesh

not touching glass
small.jpg
filled glass(with a bit of juice mesh going into glass)
full.jpg
maybe this could be fixed?

for now, the only way that I can get correct looking volume in glass is making the liquid just a very little smaller than the inside.
inside.jpg
This will of course break how refraction works on the glass edges. There has to be a way to fix it when it's inside glass mesh (volume priorities don't do anything for this issue, I tried...)

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Dade
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Re: Updated principled shader

Post by Dade » Wed Jan 01, 2020 12:02 pm

I have set up a simple test scene with a slice of glass and an overlapping volume cube:

scene.jpg

The glass has zero reflection, 100% transmission and 95% shadow transparency, it renders as expected:

image.jpg
image.jpg (10.31 KiB) Viewed 273 times

Try to set up a scene like this one for checking how/if it works. Once you have the result you want, you can go back to the real world scenario.
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Re: Updated principled shader

Post by Fox » Thu Jan 02, 2020 6:50 pm

There are some volume priority anomalies with non overlapping volumes.
c.jpg
When i use priority 0 for all,
or i use 0 for world and 3 for glass and 4 for juice,
then it looks like that:
a.jpg
But in case of 0 for world and 4 for glass and 3 for juice,
the outcome is different:
b.jpg

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