Author Topic: dubcats secret little hideout  (Read 89407 times)

2019-05-08, 21:04:36
Reply #405

tegokg

  • Users
  • *
  • Posts: 2
    • View Profile
Thank you very much Sir.

Best regards JT

2019-05-09, 17:01:36
Reply #406

Jpjapers

  • Active Users
  • **
  • Posts: 1143
    • View Profile




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





Can anyone explain this shader tree?
There seems to be no detail in this thread about what the corona colour node marked 1.8 is.
Ive tried to recreate this and that colour seems to do absolutely nothing.


2019-05-10, 11:44:09
Reply #407

niljut

  • Users
  • *
  • Posts: 2
    • View Profile




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





Can anyone explain this shader tree?
There seems to be no detail in this thread about what the corona colour node marked 1.8 is.
Ive tried to recreate this and that colour seems to do absolutely nothing.
To quote myself two posts ago:
I am fairly certain the CoronaColor is set to Solid HDR Color with 1.8 in R, G, and B, making the CoronaMix multiply your original glossiness values by 1.8x. This would make values above 141 go beyond 255, so the output has clamp enabled to bring those values down to 255.

The shader amplifies the glossiness at gracing angles, and yes it's subtle (most of the time).

2019-05-10, 12:39:09
Reply #408

Jpjapers

  • Active Users
  • **
  • Posts: 1143
    • View Profile




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





Can anyone explain this shader tree?
There seems to be no detail in this thread about what the corona colour node marked 1.8 is.
Ive tried to recreate this and that colour seems to do absolutely nothing.
To quote myself two posts ago:
I am fairly certain the CoronaColor is set to Solid HDR Color with 1.8 in R, G, and B, making the CoronaMix multiply your original glossiness values by 1.8x. This would make values above 141 go beyond 255, so the output has clamp enabled to bring those values down to 255.

The shader amplifies the glossiness at gracing angles, and yes it's subtle (most of the time).

Makes perfect sense i was missing the HDR colour bit.
Thank you!

2019-05-11, 05:41:33
Reply #409

JViz

  • Active Users
  • **
  • Posts: 43
    • View Profile
hi dubcat! how do we get correct IOR values when we do not have a scanned glossiness texture to use it with a LUT? can we use the normal texture with a LUT?

2019-05-22, 12:01:50
Reply #410

romullus

  • Global Moderator
  • Active Users
  • ****
  • Posts: 5655
  • Let's move this topic, shall we?
    • View Profile
    • My Models
dubcat, man, you'll have a lot of questions to answer next time you login. Here's one more from me :]

Lately there's a lot CC0 PBR textures floating around. Some are better, some are worse and some are rubbish, but almost all of them has height/displacement maps with arbitrary set midpoint grey (usually much darker). I found that pretty inconvenient, so i decided to fix them for myself. After few quick tests, i found that best results is achieved in photoshop by placing solid colour filter on top height texture and setting its blending mode to linear light or linear burn to lighten or to darken map respectively. Does that sounds correct to you? Do you also correct height maps or just adjust min/max displacement levels in Corona?
I'm not Corona Team member. Everything i say, is my personal opinion only.

2019-06-20, 20:09:16
Reply #411

Basshunter

  • Active Users
  • **
  • Posts: 22
    • View Profile
Hey dubcat!

It's been a long time without your presence. We miss you man.

I was wondering if you could share your opinion about what's going on with a couple of raw pictures I tried to developed using DCRAW. They were taken with my phone. I'm doing this as an experiment to help me better assimilate how a linear rendering in the VFB (without any post) should look like. The thing is that these images look horrible, almost black and white. Not even what one would expect from a linear rendering to look like.

Maybe I'm doing something wrong in the developing process. Or perhaps, I've misunderstood some concepts and this assumption of mine that linear renderings and raw photos are equivalent is wrong.

I'd highly appreciate hearing your opinion on this regard.

This is the line I've used in DCRAW to develop the pictures: -v -w -H 0 -o 1 -q 3 -4 -T
It was taken from one of your photographic LUT posts.

These are the pictures:





Original RAW files: https://we.tl/t-GHDb35EDbK


« Last Edit: 2019-06-20, 21:11:12 by Basshunter »

2019-06-22, 04:38:54
Reply #412

dubcat

  • Active Users
  • **
  • Posts: 454
  • ฅ^•ﻌ•^ฅ meow
    • View Profile
hi dubcat! how do we get correct IOR values when we do not have a scanned glossiness texture to use it with a LUT? can we use the normal texture with a LUT?
Hey!
I have a LUT that converts old reflection maps to IOR and a Corona map setup that converts normal maps to IOR. I thought I shared it a while back, maybe I never got that far. I will compile them as soon as possible!


Do you also correct height maps or just adjust min/max displacement levels in Corona?
Hey!
I've never tried the CC0 maps. If I only have a shity 8/16bit displacement map. I usually project them in Zbrush on a plane with a height value that looks reasonable. That way I can clean the nasty artifact if there are any, and export them as a proper 32bit map. When it comes to Megascans, you can get the proper height value inside the .json file, just search for "height". I don't know if Quixel have included my latest Corona exporter in Bridge 2 yet, the script takes care of all that stuff and more.


Not even what one would expect from a linear rendering to look like.

Hey!

DCRAW is really good at everything except color profiles and noise reduction. Because of this I changed my workflow a while back. My current workflow is to generate a linear profile for my camera and load the photos in Lightroom with that custom profile. I can generate a profile for you when I get time, just tell me the manufacturer and model. I'll also compile a camera curve that you can load in Coronas VFB curve editor.



I have a lot of pages to read through!
             ___
    _] [__|OO|
   (____|___|     https://www.twitch.tv/dubca7 / https://soundcloud.com/dubca7 / https://dubcatshideout.com  ( ͡° ͜ʖ ͡°)

2019-06-22, 20:14:03
Reply #413

Basshunter

  • Active Users
  • **
  • Posts: 22
    • View Profile
I can generate a profile for you when I get time, just tell me the manufacturer and model. I'll also compile a camera curve that you can load in Coronas VFB curve editor.

Sounds great! I appreciate that. It's a Moto G6 by Motorola.

However, I'd be more interested in learning how to get the camera profile and do all the process by my self. Would you be willing to share this info?

Thanks Dubcat for this thread. I really enjoy learning through it.
« Last Edit: 2019-06-22, 22:58:10 by Basshunter »

2019-06-25, 10:54:37
Reply #414

JViz

  • Active Users
  • **
  • Posts: 43
    • View Profile
hi dubcat! how do we get correct IOR values when we do not have a scanned glossiness texture to use it with a LUT? can we use the normal texture with a LUT?
Hey!
I have a LUT that converts old reflection maps to IOR and a Corona map setup that converts normal maps to IOR. I thought I shared it a while back, maybe I never got that far. I will compile them as soon as possible!


in the case of non-scan textures where a reflection or a glossiness map is eyeballed generated, is it more correct to use the normal map to generate the IOR with a LUT? I think it is, but if IOR is attached to the reflection/glossiness value and a normal map is also auto generated from photoshop or any other normal map generator, then .... (sorry for the long prelude) .... what is the correct way to getting the accurate IOR values?

thank you!

2019-06-28, 04:07:28
Reply #415

dubcat

  • Active Users
  • **
  • Posts: 454
  • ฅ^•ﻌ•^ฅ meow
    • View Profile
Moto G6 by Motorola.

This is one of those rare cases where I don't have a camera profile. You can either capture a raw photo with a mobile app and we can extract the camera profile from the raw image. Or you can generate an optimal camera profile with an Xrite, and then we can linearize the generated profile.
I hope to be more active online soon, proper linear profile guide is one of my top priories.

what is the correct way to getting the accurate IOR values?

My generator is based on IOR 1.5 and will high pass all input maps. I will port my code to 3dsMax and post it here, that way you guys can make adjustments if you want. Instead of having a static LUT.
I rarely use LUTs nowadays. Most stuff can be done with Coronas Curve editor in combination with hacky stuff between the two VFB tonemappers.

Best result would be:
#1 Specular Scan (Photo real result). (Look at your TV plastic controller, when you rotate it, it will give you micro spectacular results. But when you view it direct on, it will look diffuse. This effect can not be captured with a normal map.)
#2 Normal Map (Height Based, better than nothing.)
#3 Old Reflection custom fantasy maps (Nothing to do with real world values. 99% of online stores)

I began porting the code, and where the hell has the Corona Bitmap Blur property gone ? It was the only reason for me to use Corona Bitmap, as it behaved as a super blur for highpass.
We need a corona map that has gaussian blur, this missing feature is killing a lot of dynamic and procedural map generation ideas.

edit: typo = port -> post
« Last Edit: 2019-06-28, 05:25:38 by dubcat »
             ___
    _] [__|OO|
   (____|___|     https://www.twitch.tv/dubca7 / https://soundcloud.com/dubca7 / https://dubcatshideout.com  ( ͡° ͜ʖ ͡°)

2019-06-29, 15:49:19
Reply #416

Basshunter

  • Active Users
  • **
  • Posts: 22
    • View Profile
You can either capture a raw photo with a mobile app and we can extract the camera profile from the raw image.
Nice. There's a link to the RAW images in the original post.

proper linear profile guide is one of my top priories.
That would be fantastic. While this wonderful tutorial comes, would you mind to share some quick lines about how to get this linear profile and compile the camera curve into a LUT for Corona? I'd really appreciate it.

2019-07-03, 22:43:45
Reply #417

dj_buckley

  • Active Users
  • **
  • Posts: 251
    • View Profile
It makes no difference where you get the swatch from as long as the RGB values correlate. I just used windows snipping tool, saved the jpg to the desktop and open it in photoshop.

You can see here the swatch from the Dulux website for "Scotts Pine"
https://www.dulux.com.au/specifier/colour/colour-atlas#!/colour/dulux_dulux_21849

RGB = R: 96, G: 101, B: 58
HEX: #60653a

Attached is the photoshop color picker, the dulux website screenshot, and corona vfb render & corona color node

quick tip for you mate, if you're using Chrome browser, get the extension called Eye Dropper - you can sample the colours directly within your browser and it gives RGB and Hex etc, just checked it on the Scotts Pine one and it matches the values you got from sampling in PS

2019-07-04, 08:46:55
Reply #418

Frood

  • Active Users
  • **
  • Posts: 1270
    • View Profile
    • Rakete GmbH
get the extension called Eye Dropper

Just in case you don't know about it: you can use Corona improved Picker inside Max to sample values directly from anywhere on the screen (drag the eyedropper icon).


Good Luck




Never underestimate the power of a well placed level one spell.

2019-07-04, 18:27:15
Reply #419

dj_buckley

  • Active Users
  • **
  • Posts: 251
    • View Profile
get the extension called Eye Dropper

Just in case you don't know about it: you can use Corona improved Picker inside Max to sample values directly from anywhere on the screen (drag the eyedropper icon).


Good Luck

every day is a school day :)