Juraj's Renderings thread

[Juraj]

Ok, if you want some lulz, just search other forums

As for the albedo: do this: Find one material where you are 99% sure you know its true albedo. It can be for example a list of paper (nontranslucent). Place it side by side to real world materials and observe from multiple angles - is the paper whiter? Then its albedo must higher. So you can establish upper/lower bounds on real world albedos.

Yep, wanted to build controlled environment 1:1 where I can do measured photography to render comparison, but all this takes so much time and I need to do work instead :- )

[Ondra]

the trick is, with controlled materials, you do not need controlled environment ;)

Buying this would certainly be cheaper than building a light probe ;) http://www.bhphotovideo.com/c/product/27715-REG/Kodak_1903061_Gray_Cards.html

[lacilaci]

Pretty interesting stuff this is :D... But with corona I think for corona also MSI should be added to the equation when estimating somewhat correct cgi materials.

You can get pretty bright white walls for interior with RGB=130-150 with a little bit of reflectivity on top of that. But to make it look natural I guess you would have to go with MSI around 1000 maybe(might depend on how open the interior is).

So doesn't it make sense to go for little brighter diffuse materials when using default 20 of max sample intensity? Or am I just confused with this all? :D

[ylucic]

have you seen this Juraj?  http://patapom.com/topics/WebGL/BRDF/

it does the same as brdf explorer, but gives you control over lightning and materials. And shows you albedo values too ...It's a great webapp to play with. :) 

The albedo values there, when you load "white-paint" are about 0.75 (as a mean value, they do give you a value for each rgb channel), so I've been using this to try to imitate materials in Corona. The Diffuse Rho values are also very handy because they get red when it's over the value 1.

[Juraj]

have you seen this Juraj?  http://patapom.com/topics/WebGL/BRDF/

it does the same as brdf explorer, but gives you control over lightning and materials. And shows you albedo values too ...It's a great webapp to play with. :) 

The albedo values there, when you load "white-paint" are about 0.75 (as a mean value, they do give you a value for each rgb channel), so I've been using this to try to imitate materials in Corona. The Diffuse Rho values are also very handy because they get red when it's over the value 1.

Thank you much Ylucic ! Looks like something easier to play with :- )

[ylucic]

you are welcome ...and btw, this website has some nomenclature explained and show how "slices"  have to be read ..  http://wiki.nuaj.net/index.php?title=BRDF 

had to find that link in my old bookmarks


it would be nice to see an implementation for slices in Corona (or any other renderer for that matter) in the material editor :D

[Juraj]

Fantastic wiki article, learned quite a lot.

The white glossy paint shows albedo of 0.75, and white matte fabric only 0.3. I presume it's sum of both diffuse and specular reflectance together.
What does Diffuse Rho stand for ?

I'll leave this stuff here :- D  I compensated exposure while I adjusted different multiplier to Diffuse reflection. I kept specular reflection constant too. It uses daily build, with GGX. Its lit by HDR and Tonemapping is set to 99 to get flat shading in highlights.
I don't know how to make gif and I don't have patience.

[Stan_But]

So ? That lets me zoom. And it shows albedo value, quite lower than what I would expect.

CG artists have a long tradition of setting albedo unreasonably high because they do not understand what albedo is. As a result, rendertimes are too high and renders look washed out (so people usually end up adding ambient occlusion or decreasing light bounces :D).

I recently made again the mistake of reading up on corona on some other renderers' forums. It is always the same story - if a renderer offers an AO engine, then Corona results look "washed out and unrealistic, with no shadows in corners, probably blurred and faked as much as possible to make it render this fast"

agree to every word (;

[ylucic]

http://gifmaker.cc/PlayGIFAnimation.php?folder=2014102900DxgmONV2whOGSZTqZPfuQq&file=output_XZszDi.gif
GIF animation :D

why did you compensate exposure?? to get the "same" white? ...i'm looking at the material editor preview and there it looks more coherent the low diffuse value for white representing a greyish color

and made some comparisons with the brdf app .. with 0.9 on all rgb channels, for blinn_phong and ward, same ior for fresnel (1.5 app) and played with the roughness in specular... ..they look similar to the ones in the material editor of Corona

and I think the "Walter" analytical model is the one for GGX (Bruce Walter maybe?)

[Juraj]

Yes, to get the same brightness, because I don't know how representive is exposure inside mat editor, or what would be the correct one to judge materials.

Damn you're pretty good with the app, I didn't know I can make my own test like that :- )

[Jacinto Monteiro]

Hi, great work and topic!

Just two quick questions:

In the Norwegian house for outside and inside which Cgsource HDRIs did you use specifically?

Same project, the interior wood boards are they cgsource texture too?

Cheers,
Jacinto

[Juraj]

It's called Iceland :- )

Texture see my last reply in gallery thread, I write few alternatives, unfortunately this one (not because of me only) I can't share, it's not possible to buy or get it.

[chrisc0le]

If anyone was bored and wanted to watch something educative, we already started posting the videos online, but for now, they are in slovak language. They will be re-voiced fully in english after they are all complete, in early February. By that time, there should be around 20 videos and around 20 hours of free material.
We create them and publish them after our Friday's classes at Uni are over, so far there are 2 basic modelling videos.

[so disclaimer: might only hold value for total beginners right now, but eventually will go very complex, and until February only Slovak voice (Veronika and me, plus some of our modelers for SubD), in February English voice (again us) plus english subtitles ]

Just wanted to put it up in case some slovaks/czech/people who don't care about voice would look it up.

We'll supply full files for every stage by then too, right now, if someone wants the Cad files, just write me or maybe I'll post a link. It's just basic stuff Veronika drawn in AutoCad to simplify it.
At the moment it's only HD1280px, but english version will come on my VimeoPro so it will show in its original fullHD quality.

]

Hi Juraj, hope you had a good weekend.
Is there anywhere I can download the autocad files for these videos?

Thanks
Chris

[Juraj]

Oh yes, moment, I'll ask Veronika where it is, and upload them when I find them on disk.

[chrisc0le]

Oh yes, moment, I'll ask Veronika where it is, and upload them when I find them on disk.

Superstar :) Thanks.