Author Topic: HOW TO: Make a Calibrated Material Scene  (Read 22409 times)

2017-10-06, 02:05:35

dubcat

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OLD THREAD PLEASE DELETE
« Last Edit: 2019-12-29, 02:13:44 by dubcat »
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2017-10-06, 10:44:15
Reply #1

Fluss

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Awesome stuff as always! Thank you for sharing your knowledge! 👍

2017-10-06, 12:11:20
Reply #2

johan belmans

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2017-10-06, 13:24:04
Reply #3

nkilar

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Dude, you are something else... Thanks! :)

2017-10-06, 13:57:33
Reply #4

Juraj Talcik

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Straight into PBR Bible :- )
talcikdemovicova.com  Website and blog
be.net/jurajtalcik   Our studio Behance portfolio
Instagram   Our studio Instagram, managed by Veronika

2017-10-09, 09:33:22
Reply #5

srikken

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Super, Thank you!



The ColorCehcker Passport, would it be better to just use it as a bitmap or make an individual material for each color and model a simple ColorCehcker Passport?

2017-10-09, 13:22:33
Reply #6

Alexp

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18% grey or 13%?

I found a nice document to explain the difereces. In perfect spanish. And Im a bit confused.
https://blog.foto24.com/carta-gris-que-es-como-usarla-exponer-correctamente/#

2017-10-09, 13:55:01
Reply #7

burnin

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^ Google Translation to English > Gray card: what it is and how to use it to expose correctly

Confused about?
18, 13 or 12% - Is your choice, as you see it acceptable...

Quote
This value each photographer must decide whether it is acceptable or not.
« Last Edit: 2017-10-09, 14:02:01 by burnin »

2017-10-09, 13:59:58
Reply #8

Alexp

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^ Google Translation to English > Gray card: what it is and how to use it to expose correctly

Confused about?
It's your choice, as you see it acceptable...

If we need to take reference from 18% grey or 13%

2017-10-09, 14:04:10
Reply #9

burnin

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Updated the previous post.

Personally, i always deviate a bit... it's a personal style, preference.
As long as you know what you're doing.
;)

2017-10-10, 13:02:46
Reply #10

dubcat

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Hey guys

The important thing is to have a properly lit color reference next to whatever you want to capture. Capture the color reference as close as possible to the specified value. Adjust the raw image in post until the values match 100% to the specified value.

Once you have calibrated your HDRi inside Corona. It doesn't matter what diffuse color the sphere has, because the sphere will always be correct. If you change the color from 18% to 90%. The brightest part of the sphere should be 243 sRGB in VFB.

Since we are using 0 glossiness the white will dim a little. I'll remove the reflection/glossiness part from the main post later, so it dosn't add any confusion.
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2017-10-12, 16:58:43
Reply #11

romullus

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Materials with proper ColorChecker values will look very flat and boring. This is how it should look.
Linear raw photos are just as boring.

You can toggle one of my photographic LUTs to see how the material will look in a final render.

So should i do authoring of materials without tonemapping and only occasionaly turn tonemapping on, to see how final result will look? Also, the thing is that whenever i use one of your photographic luts, i feel that i always need to turn down exposure by 2/3-1 stop. Normally that isn't a problem, because i turn lut on, turn exposure down and continue working on other settings, but if i'd have to constantly fiddle with lut and exposure settings just to check how material will look with proper tonemapping, that would be very tedious. Or maybe i completely misunderstood workflow?
I'm not Corona Team member. Everything i say, is my personal opinion only.

2017-10-12, 19:58:17
Reply #12

dubcat

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Or maybe i completely misunderstood workflow?

Hey man!

You are spot on. The main objective is to calibrate the light source, so you know the brightest part on the object is the actual albedo.

Like you said, you have to be in full linear default mode to see the real values, but use tone mapping and LUTs to see the final result. I usually save both settings and just hit load in VFB.
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2017-10-12, 20:10:35
Reply #13

romullus

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Save/load might be good idea, i'll give it a try. Thanks!
I'm not Corona Team member. Everything i say, is my personal opinion only.

2017-10-13, 16:07:07
Reply #14

johan belmans

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Hi Dubcat,

Can you explain me why it is important to desaturate the HDRI with a color correction node together with desaturating the VFB.
Because to me it seems illogical too desaturate twice.
Although I noticed you get different sRGB values.