Chaos Corona Forum

General Category => General CG Discussion => Topic started by: Juraj on 2015-01-16, 22:03:00

Title: New diffuse shaders from Sergey Shliaev
Post by: Juraj on 2015-01-16, 22:03:00

I wish you could just hire this guy. Another interesting implementation. Little things, but so cool.

http://www.shlyaev.com/rnd/37-cpp-category/60-diffuseshaders

(http://www.shlyaev.com/images/stories/diffuse/wing_closeup.jpg)

Title: Re: New diffuse shaders from Sergey Shliaev
Post by: steyin on 2015-01-16, 22:10:42

(http://i.imgur.com/gVALmlw.png)

Title: Re: New diffuse shaders from Sergey Shliaev
Post by: daniel.reutersward on 2015-01-16, 22:23:46

That is really nice, those details add quite a lot!

Title: Re: New diffuse shaders from Sergey Shliaev
Post by: lacilaci on 2015-01-17, 09:07:50

Now that's some magic...  Is there way to maybe emulate the looks? Did you try?

Title: Re: New diffuse shaders from Sergey Shliaev
Post by: Juraj on 2015-01-17, 11:54:16

No I didn't. Perhaps some AO or special diffuse fallof curve could provide something of that sort.

Title: Re: New diffuse shaders from Sergey Shliaev
Post by: Ondra on 2015-01-17, 11:57:00

This looks very simple to implement. Perhaps in the future there will be an API for creating custom BRDFs in Corona

Title: Re: New diffuse shaders from Sergey Shliaev
Post by: Ludvik Koutny on 2015-01-17, 16:59:21

The thing is that in real world, almost all of the non-metallic materials have some (even if tiny) amount of SSS, and from the picture comparison, to me it looks like lambert model is better at fooling eye into believing the material has tiny bit of SSS going on since shadow falloff is softer. In reality it would be crazy to make everything in your (for example interior) scene covered by SSS materials.

I am all for it, but i would not replace Lambert with it. For example Vray and MR have a roughness parameter next to diffuse, which blends Lambert with rough Oren-Nayar model. So perhaps corona could have one that blends between Lambert and Full moon :)

Title: Re: New diffuse shaders from Sergey Shliaev
Post by: Ludvik Koutny on 2015-01-17, 17:03:35

Heh, actually i just found out Oren Nayar may be an older attempt to approximate same diffuse reflectance model :)

(http://www.sfdm.scad.edu/faculty/mkesson/vsfx755/wip/best/spring2012/kevin_george/final/thumbs/diffuse_models.jpg)

Source: http://www.sfdm.scad.edu/faculty/mkesson/vsfx755/wip/best/spring2012/kevin_george/final/index.html

Title: Re: New diffuse shaders from Sergey Shliaev
Post by: Juraj on 2015-01-17, 17:28:18

Quote from: Rawalanche on 2015-01-17, 16:59:21

I am all for it, but i would not replace Lambert with it.

No I don't wish so either, I don't think the author was comparing them as equal, just as visual comparison purely to judge the behavior.

The Disney's research paper showed some additional contenders to Lambert for regular use.

Interesting to know that's what Vray's roughness does (blending with O-N), I always just knew it adds "dusty" feeling but never found occasion where to try it.

Title: Re: New diffuse shaders from Sergey Shliaev
Post by: agentdark45 on 2015-01-17, 18:03:10

Wow the details really pop out more in the comparison images on his site.