Author Topic: New Corona Physical Material (PBR) playground!  (Read 39895 times)

2021-06-15, 23:42:19
Reply #195

Yuriy Bochkaryov

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PhysicalMaterial: IOR 1.52 translates as Specular 0.5 (this is industry standard formular, Corona didn't make it up, look Unreal or Substance documentation)
if this is really a new industry standard, then you have to get used to it, this is not a problem. It just looks strange to me and I am worried that it may turn out to be a mistake, I will do a lot of work on my library, and then the development team will recognize it as a mistake and change the algorithm and it will break my whole library, it will be a very unpleasant surprise )

2021-06-16, 00:51:10
Reply #196

lupaz

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As mentioned before, it's not about the money or anything else, he wanted to move on to other projects that were not tutorials. We will be having new tutorials though, and with an equally awesome presenter, so never fear in that regard :)

Great.

2021-06-16, 02:14:23
Reply #197

cjwidd

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just so I'm clear, if I set the IOR to 1.52 and I pass in a bitmap that contains black and white pixels, the white pixels will render as 1.52 IOR and the black pixels will render as 1.0 IOR?

2021-06-16, 10:05:16
Reply #198

romullus

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No, the moment you assign a map to IOR, its spinner value gets ignored and the map values are read depending on its dynamic range, like it's described in maru's message above. So in your example (asuming that we're talking about low dynamic range image), white pixels would represent IOR 1,0 and black pixels woul go for IOR 999
I'm not Corona Team member. Everything i say, is my personal opinion only.
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2021-06-16, 12:09:12
Reply #199

Yuriy Bochkaryov

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we still have an open question - why increasing texture brightness starts to work as an invert for IOR
texture through color correction with RGB 500 - works correctly
texture through color correction with RGB 700 - starts to work as inverted. why?
Why does increasing the brightness of the bitmap change the reflection value of the IOR to inverted?

2021-06-16, 15:12:00
Reply #200

romullus

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I think that's happening because when you're increasing value intensity, pixels that didn't reach value of 1 yet, are treated by the different set of rules than pixels that are over 1 already. In other words, while pixel's value is increasing in 0-1 range, its represented IOR is decreasing and approaching 1,0, but as soon as that pixel's intensity goes beyond 1, its represented IOR starts increasing and approaching max value, i.e. IOR 999 I always though that this behaviour is global and uniform per map, but it looks that it's being calculated per pixel. I know it sounds complicated and i might be completely wrong, so it would be nice to get confirmation (or denial) from the team.
I'm not Corona Team member. Everything i say, is my personal opinion only.
My Models | My Videos | My Pictures

2021-06-17, 11:54:44
Reply #201

Yuriy Bochkaryov

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The development team is silent and we cannot understand whether this is normal or is it a bug.

2021-06-17, 15:31:52
Reply #202

maru

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we still have an open question - why increasing texture brightness starts to work as an invert for IOR
texture through color correction with RGB 500 - works correctly
texture through color correction with RGB 700 - starts to work as inverted. why?
Why does increasing the brightness of the bitmap change the reflection value of the IOR to inverted?

Most likely, this is happening exactly because of what I explained in my previous posts:
- if the value is above 1, it is directly applied as IOR (e.g. value 1.5 = IOR 1.5)
- if the value is below 1, it is converted into 1/IOR (e.g. value 0.5 = 1/0.5 = 2)

But to make sure, it would be great to check the specific scene that you are using. Could you please send it to us? The uploader is in my signature below.
Thanks in advance!

I will be sure to look into this myself and in case of any doubts discuss this with the other teams.

2021-06-17, 18:18:37
Reply #203

maru

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Despite being a non-developer, I am breaking the silence! :)

Please check this video, I hope it clearly explains the behavior we are observing here:

2021-06-17, 18:57:24
Reply #204

cjwidd

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I needed this, thank you +1

2021-06-17, 21:57:18
Reply #205

scionik

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Despite being a non-developer, I am breaking the silence! :)

Please check this video, I hope it clearly explains the behavior we are observing here:


Thank you for explaining this case.

2021-06-17, 23:14:45
Reply #206

Yuriy Bochkaryov

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Despite being a non-developer, I am breaking the silence! :)

Please check this video, I hope it clearly explains the behavior we are observing here:
Thanks for the info.
Now it looks very strange, but you can get used to it.
The main thing is that the developers do not change anything in the future, which will lead to the breakdown of our materials made now on the new physical shader.

2021-06-18, 09:23:16
Reply #207

maru

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I am still interested in seeing examples of:
- materials that are using IOR textures
- how materials with IOR textures are exported from various commonly used apps - what format are they exported to, what is their bit depth

2021-06-18, 09:26:09
Reply #208

cjwidd

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Everything from Designer and Painter, Megascans to a lesser extent.

2021-06-18, 18:49:47
Reply #209

pokoy

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I am still interested in seeing examples of:
- materials that are using IOR textures
- how materials with IOR textures are exported from various commonly used apps - what format are they exported to, what is their bit depth
As for materials with reflection color or IOR textures, basically anything with varying reflection amount on its surface:

- wood
- any sort of stone and minerals (with the exception of those polished for high gloss maybe)
- concrete, especially when mixed with additional stones or gravel etc
- skin (tiny sweat droplets etc)
- metals - almost any metal that's been touched/used will feature oxidation, impurities or stains etc that will result in varying reflection levels
- manmade surfaces that have seen any usage

The more I think about it, the more I'm convinced that almost everything will display varying reflection level. Absolute perfection will look artificial... an exception would be a water surface, maybe :D