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Messages - dubcat

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1
Lol exactly, yes, input values would be great. To be sure, I am envisioning something more like this:



+1

2
I would love a Level Adjustment feature. But actual value input in the current Curve editor would go a long way!




3
Work in Progress/Tests / Re: dubcats secret little hideout
« on: 2019-10-04, 03:39:42 »
Dunno but I think something's not right with the girl's brows.

hehe

images are a lot more "analogue" in the way noise is distributed/cleared, it's quite a lot closer to film.

I know exactly what you mean!
I was talking with the devs a year ago or maybe two, and this feature was included in the early Corona builds, but they had to remove it for some technical reason.
You can manually adjust the "Image Filter (Width [px]) in Systems or find VFB blur setting that mimic this 1 perfect pixel 50% side blur effect. VFB blur has to be adjusted if you change render size.

fstorm sample



corona sample



And as far as I know, Corona IS actually using GGX shader?
Yes as nkilar responded.

4
Work in Progress/Tests / Re: dubcats secret little hideout
« on: 2019-09-28, 03:41:17 »
+1 on the learning of how to extract and make usable LUTS from specific camera profiles, I have a D810 and I'd love to being to extract the response curves of the various picture modes (Standard, Neutral, Flat, Landscape etc) and use them as LUTS or Curves in VFB.  It would make camera matching lighting and colours an absolute dream

Noted!

To me it looks like reflection gets sharper towards the light source, just like in fstorm, but maybe I'm wrong.

The devs told me that this effect should be included in the GGX shader.

Is it still working? apparently you blocked PMs

I didn't have much time to be active on Discord, so this project was a big fail on my side. Sorry about that. I really feel bad about the whole Discord situation, sorry again for everyone that joined. I really appreciate you.

---------

Sylvanas Windrunners facial animation and those teeth in the last Blizzard Cinematic is just unreal! GG!
I usually dread CGI trees and CGI teeth, but damn, Blizzard got it right this time.




5
I take it youre an fstorm user now?

Hey!

I still use Corona / 3dsMax professionally, but I always stress test other render engines. My current absences is not the result of an engine switch. I'm happy with the current Corona development, but there are currently two SUPER important features that are lacking in Corona. Fabric BRDF ( You have to copy paste the URL, the direct link URL will redirect you to the index) https://blog.selfshadow.com/publications/s2017-shading-course/imageworks/s2017_pbs_imageworks_sheen.pdf and Burley Diffuse Roughness https://disney-animation.s3.amazonaws.com/library/s2012_pbs_disney_brdf_notes_v2.pdf.
Both these features are included in MaterialX https://www.materialx.org/assets/MaterialX.v1.37.PBRSpec.pdf that even Substance Designer/Painter has implemented.

6
Hey!

I'm having a hard time sleeping and thought, why not do a random dubcat google search, and here I am.

RAL 7038 is pretty easy to convert to Albedo. RAL 5008 will get clamped because the LRV is 4%. I don't know if Autodesk is the culprit, but both Corona and Vray will clamp these values to 0 RGB.



edit:

I forgot to answer the gloss question. Real world materials usually don't go bellow 0.4 PBR glossiness. 13 gloss level does not equal to 0.13 pbr glossiness.

This is fstorms glossiness level mapped to PBR glossiness.



Current PBR glossiness does not exceed the material IOR. So if you do a cross polarized material scan of asphalt, and normalize the scan based on the F0 of the asphalt. And generate a glossiness/roughness map base on the asphalt F0. The gem stones in the asphalt will not have the correct IOR. Because the gemstones can not exceed 1.5 IOR. We need a new shader that read both glossiness/roughness and IOR/Specular at the same time. Modern render engines can not fake this stuff with geometry. Corona is stil using complicated IOR instead of real world easy math Specular.

7
Work in Progress/Tests / Re: dubcats secret little hideout
« on: 2019-06-28, 04:07:28 »
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

8
Work in Progress/Tests / Re: dubcats secret little hideout
« on: 2019-06-22, 04:38:54 »
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!

9
Work in Progress/Tests / Re: dubcats secret little hideout
« on: 2019-02-16, 02:02:38 »
I've been analyzing a bunch of professional Scandinavian interior photos (that still contained lightroom exif data, we can extract this data, and remake the original photo. It won't be 1:1 to the original, but it will get us in the ballpark), and this is the average color matrix they all use.
I was wondering how close we could get to this color matrix using Corona VFB Saturation. -0.075 seem to get us pretty close.
I found it interesting that Coronas VFB Saturation is not "linear" in the way that all the colors get reduced (You can see that blue gets reduced more). I'm not complaining (since this is how the photos are behaving), just found it interesting.


10
Work in Progress/Tests / Re: dubcats secret little hideout
« on: 2019-02-09, 22:31:26 »
Why not just use the hex color code if you want to match the paint in the corona color picker? Still a workaround but none the less it gives accurate results correct?

If you already have the paint value with correct LRV and - IOR, this solution works fine. The paint swatches that most companies use in Norway do not factor LRV/IOR.

You can see here the swatch from the Dulux website for "Scotts Pine"

Looks like Dulux take LRV and IOR into account on their online swatches, if only all paint manufactures did this.



But you can do that with CoronaColor texmap too, why use Vray's map?

The thing with CoronaColor is that if you switch to "Solid HDR color", it overwrites the color you have sampled. While VrayColor does not force any workflow, you can sample the color and still have linear float.


11
Work in Progress/Tests / Re: dubcats secret little hideout
« on: 2019-02-08, 04:08:15 »
I remember you did a thread on virtual colour checkers.
How would that work with ACES Emulation?
Would you apply aces settings and your LUT and then use the output in lightroom to calibrate?
Colour management is all very new to me but its infinitely fascinating to get into the process of making sure my work output is accurate.

Hey!

I would capture a color checker passport at your current light intensity. Generate a camera profile. If your profile has a contrast curve, open it in 3DLUTCreator and remove it. This should give you a calibrated color and linear camera profile.
When you have a calibrated profile. The only thing you should care about is linear values. When it comes to real world albedos, we talk in linear %. If I tell you the brightest common paint is 94%, you should be able to input that value into "Value" in Corona Picker. But that is not how Corona Picker is working right now. So you have to convert 94% to sRGB. If you are thinking, why the hell do we have to gamma correct a linear value only to get a linear value, ask the Corona devs, it blows my mind every day. 94% is 97.2% sRGB, so this is the max real world scanned common paint value.

Another problem we have with the current Corona Picker is that the darkest common paint is "Jet Black" and it's 14,14,16 sRGB. Try to input these values into Corona Picker. You end up with 0,0,24 sRGB. This is a common problem when we try to sample real world values for products, the sRGB values might jump 10 sRGB. I'm using Vrays color map to fix this, because it let me adjust values separately with float values.


-----------------------------------------------------------------------------------------------------------------------
edit:

I haven't had much time to complete the last few guides on my site. But I want to share paint values with you guys as soon as possible, so I have remove all the unfinished stuff from the site.
I've only had time to add the 2019 Color Chart paints to the page, but have about 1 gazillion paints ready.
If you have a paint value, and are wondering how it would look with LRV and - IOR. Just post the values here, and I'll add them to the page when I get time.

https://dubcatshideout.com/

12
Off-Topic / Re: catnip sessions
« on: 2019-02-03, 05:53:50 »
catnip sessions (Top January 2019)

ฅ^•ﻌ•^ฅ meow purr purr.



01. Catnip Sessions - Intro
02. Hardwell feat. JGUAR - Being Alive
03. Terry McLove - Alive (MOTi Edit)
04. Madison Mars x Lucas & Steve - Lunar
05. Habstrakt - Darkness
06. Wolfpack & Eastblock Bitches - Apache Anthem
07. Mike Williams - I Got You
08. Deniz Koyu - Eclipse
09. Klaas - Figure Out
10. ALOK & Timmy Trumpet - Metaphor
11. Juicy M vs. Subshock & Evangelos - Psyhaus

13
Work in Progress/Tests / Re: dubcats secret little hideout
« on: 2019-02-03, 04:42:46 »
Fstorm has so many useful features like that and I wish they were higher on the agenda for corona.

For sure!

It was plugged in, that's a gamma issue for sure, I'll prepare you an explanation of what's going on.

Me and Fluss will be having some direct messaging. Just letting you guys know, so you don't think I'm an asshole that ignore all his posts :P

P.p.p.s. Your LUT is correct, my fault, i don't understand why 167 instead 170... Bah!

Hehe, I feel you! 3dsmax slate and linear/srgb is a real pain in the ass. Software that compile LUTs are also a pain in the ass, there is no standard.
I will be supporting Corona/Vray/fStorm/Octane/Renderman and Blender 2.8 on my site in the end. (Corona is always first priority)
I have high hopes for Blender 2.8, finally I can click on that damn default cube with my left mouse button and delete it. Can't wait to code my procedural mask generator!

14
Work in Progress/Tests / Re: dubcats secret little hideout
« on: 2019-01-31, 02:45:12 »
There is a really strange behavior I cannot explain. After further testing, it looks like it's the 1/IOR part that not working here. On the render result at least as the material preview and the rendered material do not follow the same behavior.

Weird stuff.

This is how it is supposed to look like when you use my setup



And this is how a normal Corona material looks like without the IOR combo. A reflection pass that only a mother can love.



Looks like the exposure inconsistency is related to the gamma 2.2 part in the IOR mask generation.

From the screenshots it looks like you didn't plug the highpassed linear roughness map into the mask slot ? Hard to tell since the screenshot is clipped off.


This material is a perfect example on why we should use cross specular maps as IOR maps https://quixel.com/assets/tbxkajlk

edit:
I overlooked the first response, sorry!

How do you have such knowledge of the technical aspects of lighting and shading?

It all began with Half Life 1 and Sims 1. The first thing I noticed when making textures for these games, was that I could have a static camera and move a light around (at the same distance). Then I could blend multiple photos together with "Lighten", this blending mode will only lighten dark pixels (shadows) and make an "albedo". Back then I didn't know what an albedo was, but it was good enough to import into Wally and make a .wad. I used to hang my cloths up, take a picture and then use the transform tool to turn them into the Sims 1 skin format, good times.

Half Life 2, Doom 3 and Oblivion opened my eyes when it comes to normal map and parallaxing effect. fStrorm still does volume displacement, and it's
 fuc***g awesome. https://fstormrender.ru/manual/displacement. Ever wondered why fStorm users can use displacement on every single plant in their interior, and why the displacement only take like 400mb instead of 200 gazillion terabytes ? This is why.

When Quixel began posting beta versions of roughness, I understood that the next step was to get my hands on some polarizing filter. You can get good quality sheets from https://www.polarization.com/polarshop. I still use sheets from these guys, even though I have to pay almost double the prize in tax, only to import it.

Since then I've been doing SSS, IOR and albedo tests on my own.
When it comes to SSS. Shorter wavelengths (blue) gets scattered more easily than red light. This is why skin looks red when you shine a light thought it, not because of the red blood. Scatter color in render engines should only be monochrome or blue to be physical correct.

You already know my view on glossiness/ior integration. Again, download https://quixel.com/assets/tbxkajlk and have a look at the glossiness map. This is not possible with normal maps.

15
Why is it that Dubcat believed the disable IOR node was helping, but it is being suggested here that it is not making a difference.

You could disable IOR like in Vray a few patches ago. In the latest Corona version you can't, and I have no idea why the devs would go with this decision.

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