dubcats secret little hideout

[dubcat]

I've ported Metallic Shading from Unreal 4.
The falloff has bright edges, dark middle and semi bright center.
In Unreal 4 you are only allowed to change the Base Color, but you can tweak the gamma inside the Pow maps for different looks.

Basic shader to show the effect





I've also updated the Fuz shader.
- Fixed some math in the Core Darkness section.
- I realized that pow is the same as inverse gamma, so now you can adjust Power the same way as in Unreal 4.

Transition from rock to moss doesn't look that good.

This has to do with Edge Brightness, I had it at 1 during testing.

[rambambulli]

Professor Dubcat,I love it! I have been looking for this to hook the curvature, positionmaps, etc. to some Substances I made.

[dubcat]

Megascans Studio heightmap based blending inside 3dsMax





edit:
The Gamma 2.2 map is there because Output Map is linear, and we want to emulate Levels in Photoshop.

[dubcat]

Edit: Bug in my auto script, will post update when it's sorted out.

[romullus]

I thought that after most recent changes in Corona material (PBR mode), its glosiness matches 1:1 with Vray GGX, isn't? :/

[dubcat]

I thought that after most recent changes in Corona material (PBR mode), its glosiness matches 1:1 with Vray GGX, isn't? :/

It should be closer, I noticed a bug in my vray script. The fstorm table is accurate. I'll wait until the table is 100% complete before I post it again.

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Here is a little "how to get that fStorm look in Corona" post.

I've attached a little Photoshop script that will turn your harsh Corona renders into soft fStorm renders.
This blur/sharpen effect really help sell that photorealism, when did you capture a picture with your camera and the noise was pixel perfect ? (I'm not talking about ISO 1million)

If you are using Arion to add chromatic aberration, you will already have a blur like this (- the sharpen), since this is a side effect of the R G B transform. But this Photoshop script is shifting R G B equally.
If you do an anti chromatic aberration operation in CameraRaw after Arion, you will see that your render still looks more Photorealistic after the anti chromatic aberration operation. This is because the blur that is the main ingredient.

This stuff should be included in Corona frame buffer. Go and +1 on mantis!



and this is how you can emulate fStorms "Angle Affect" option in Corona



In fStorm the "Angle Affect" parameter goes from 0-1. After some quick testing, this looks to be the same as IOR 1.5 - 3
I've made a little improvement to the effect. You can specify a value that gets multiplied with the base glossiness. This is nice for rough materials, where you don't want the edges to be 255 glossiness.
So tweak IOR and the multiply value to taste.

This feature should be included in Corona if you ask me! I notice this effect each time I lay down, even on rough fabrics.
Next time you lie down in bed or drunk on the floor, try to look for this effect, and then go and +1 mantis!





I've also attached two LUTs that emulate the default 0.3 contrast in fStorm and a 0.15 contrast version. The contrast slider in fStorm don't affect white, so it's more of a black crusher. The effect can be really strong, so you might want to tone it down.
This is 0.15 contrast



-1 HC in fStorm that has kinda become the standard, is 50 hc in Corona!

fStorm is caped at around 0.40 Corona glossiness. Which is a bad thing, but now you know.

Another thing that Corona is still missing that both fStorm and Vray has, is focus pick in frame buffer. +1 mantis if you are missing this feature!
You won't believe how amazing it is to build your scene. Walk around as a photographer, focus pick in frame buffer. CTRL + C, render afterwards. This is a MUST feature.

fStorm renders object with no material as default material, instead of random object color.

So there you go, if you follow these guidelines you will get that cRona look!

Don't forget to Mantis, shit won't happen if you don't act! Spread the words to your friends.

[dubcat]

edit:
These LUTs ship with Corona 1.6

I've been dumping cameras as LUTs for the past 6 months or so.
Here are 3 of those dumps.
Think of your renders as "linear raw" files from your camera, these LUTs do the camera processing (what your JPGs looks like in camera).
(By "linear raw" I mean (dcraw.exe -v -w -H 0 -o 1 -q 3 -4 -T), not CameraRAW/Lightroom import!)

You don't have to use them at 1 opacity. If you apply "Photographic 01" with 0.68 opacity, it mimics another camera. So feel free to experiment.

With these LUTs you can use 30 sRGB black / 210 sRGB  white in your materials, and they will look nice and contrasty in your final render.

These LUTs make your linear render look like a processed camera photo, it's up to you if you want to take it any further in CameraRAW/Lightroom. I always end up doing some kind of local processing in CameraRaw.

I want to give Juraj Talcik and Peter Guthrie credit for giving me valuable feedback while I dump these cameras (and still do). So thank you super duper mega very much!

Here are some quick test renders to show the general behavior
As you can see, they all have the same kind of contrast, but the HSL adjustments differs a lot.









What LUT is your favorite ? Did it improve your render ? Let me know ! (If you find weird color shift problems or anything like that, contact me).

edit:
Here are the render settings. These Sharpening/Blurring settings will give you that nice fStorm noise.



edit:
Attached EV normalized versions so you don't have to reduce EV.

[pokoy]

This looks good! Will try next week - thanks for sharing them!

[Correntes]

yeah i will test it too.

will see how it compares with exact reference photo

[olotl]

this is a really nice thread! lut's working great - thanks a lot.

[miaz3]

@dubcat :

I find it strange to use LUT that is not related to the digital depth of the image rendered ?!
If I open the LUT there is only 32,768 correction line (2 ^ 15). But if you work on a 16bit image it would take 65,536 (2 ^ 16) lines of corrections ...
So why lost the half data ?

[sebastian___]

Great thread. What cameras are used for the extracted LUT ?

[Ondra]

@dubcat :

I find it strange to use LUT that is not related to the digital depth of the image rendered ?!
If I open the LUT there is only 32,768 correction line (2 ^ 15). But if you work on a 16bit image it would take 65,536 (2 ^ 16) lines of corrections ...
So why lost the half data ?

you are not actually losing anything, this is resolution of the mapping function, not the input data - even low-res mapping function can be used to transform high-res input data with no quality loss.

As an example: Corona VFB uses 32bit color format. If you change exposure, you are applying a transformation that could be expressed as 1 line LUT. But the output image does not lose any information

[Correntes]

Dubcat:

I prefer your PhotographicCurve v2  lut that you previously shared with albedos white 240  black 50 srgb corona contrast 4

30black/210white plus the luts seems to dark/contrasty and washout textures.

With the PhotographicCurve v2 setup i get an almost perfect material editor preview match up with the actually rendered.
Maybe I'm doing something wrong but this setup is a lot more predictable

[Nejc Kilar]

Dubcat:

I prefer your PhotographicCurve v2  lut that you previously shared with albedos white 240  black 50 srgb corona contrast 4

30black/210white plus the luts seems to dark/contrasty and washout textures.

With the PhotographicCurve v2 setup i get an almost perfect material editor preview match up with the actually rendered.
Maybe I'm doing something wrong but this setup is a lot more predictable

With white color at 240 I presume the render times have fallen of the charts (super high), right?