Page 1 of 1

Back painted glass with AO... is it possible?

Posted: Tue Jan 21, 2014 1:53 pm
by happymilk
Hi to all (and excuse me for my terrible english)
Is there any way to make a good back painted glass with the AO kernel?
I did two test (see attachments) with AO and PMC.
Glass is standard specular material (with fake shadows on, but without is same)

I would like to have the same PMC result using the AO kernel.
Thanks for all :)

Re: Back painted glass with AO... is it possible?

Posted: Thu Jan 23, 2014 3:24 pm
by NVN
use "Diffuse" and not AO
Its looks for me a bitter like PT

Re: Back painted glass with AO... is it possible?

Posted: Thu Jan 23, 2014 7:42 pm
by happymilk
You're right NVN
Infortunately Diffuse is slower than AO.
Also in this specific case the kernel Diffuse fails to illuminate the back of the glass

Re: Back painted glass with AO... is it possible?

Posted: Thu Jan 23, 2014 8:30 pm
by stratified
This is how ambient occlusion works, the whole backplane is ocluded by the glass plate so it's dark.

cheers,
Thomas

Re: Back painted glass with AO... is it possible?

Posted: Fri Jan 24, 2014 8:41 am
by suvakas
Would it be possible to implement smth like "exclude from AO" ?

Suv

Re: Back painted glass with AO... is it possible?

Posted: Fri Jan 24, 2014 9:22 pm
by stratified
I guess it's not worth it. AO is a "hack" to speed things up. If we have to do extra stuff while calculating ambient occlusion it won't be fast anymore and it defeats the purpose of AO in the first place.

The best thing is to use PT or PMC when things don't work out with AO.

cheers,
Thomas

Re: Back painted glass with AO... is it possible?

Posted: Wed Jan 29, 2014 8:12 am
by suvakas
But wouldn't it still be faster than true PT or PMC? There are engines that are doing it. (one specific "one man" renderer for Max just announced it).

Suv

Re: Back painted glass with AO... is it possible?

Posted: Wed Jan 29, 2014 9:47 am
by bepeg4d
hi,
some time ago, marcus has solved the issue for the specular material with ao.
so if you use a specular material with sss for the back part, it works pretty well ;)
Capture-specular-glossy.JPG
ciao beppe