Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: AnubisMe on 2013-03-09, 20:13:41

Title: Caustics, refraction, glass questions.
Post by: AnubisMe on 2013-03-09, 20:13:41

Hi all. I am trying to design a perfume bottle and wondering a couple things. Does Corona support caustics yet? And if so how do I go about activating them. Also whats the best way to give glass that thickness look, I am still confused about when to use solid face vs thin faces. Also in vray there was the fog setting in material to change colour settings of say water ect. is there anything like that in corona that I am overlooking?

thanks in advanced.

Title: Re: Caustics, refraction, glass questions.
Post by: Ondra on 2013-03-09, 20:22:27

hi,
caustics are always there, only sometimes they get clamped. You can set maximal sample intensity to 0 to get unbiased result, but you will probably get some fireflies. There are other algorithms for rendering caustics, but not in public beta, you'll have to wait for alpha 4 (1-2 weeks).

Use solid glass, thin is for windows.

There is absorption parameter in coronamtl working like vray fog

Title: Re: Caustics, refraction, glass questions.
Post by: AnubisMe on 2013-03-09, 23:42:43

This is about how far I have got playing around with the glass. I am not sure what I am missing so far, but I have seen a lot stronger results in the gallery.

My aim is to make something like this: http://www.jarrold.co.uk/UserData/root/Images/Beauty%20Images/Perfumery/L'Artisan/seville-a-l'aube.jpg

Title: Re: Caustics, refraction, glass questions.
Post by: Polymax on 2013-03-10, 08:37:40

At this stage, only the GI caustics possible. Use IBL!

Title: Re: Caustics, refraction, glass questions.
Post by: AnubisMe on 2013-03-10, 17:58:20

IBL? From reading a lot of the posts people seem to mention a lot of things that I have not seen with the Corona render? are they hidden?

Title: Re: Caustics, refraction, glass questions.
Post by: Polymax on 2013-03-10, 18:07:39

Quote from: AnubisMe on 2013-03-10, 17:58:20

IBL? From reading a lot of the posts people seem to mention a lot of things that I have not seen with the Corona render? are they hidden?

Put HDRI texture in enviroment and no more light.

Title: Re: Caustics, refraction, glass questions.
Post by: AnubisMe on 2013-03-10, 18:23:57

yeah I already had a HDRI in the scene under Corona environment, so your saying its best not to use Corona lights with HDRI then?

Title: Re: Caustics, refraction, glass questions.
Post by: Polymax on 2013-03-10, 18:51:32

yes, only HDRI! My work form the gallery, there is only HDRI:
http://forum.corona-renderer.com/index.php?action=dlattach;topic=452.0;attach=1779;image

Title: Re: Caustics, refraction, glass questions.
Post by: AnubisMe on 2013-03-10, 18:57:18

that looks incredible! Yes that is the type of quality, and look I am going for.

Title: Re: Caustics, refraction, glass questions.
Post by: AnubisMe on 2013-03-10, 20:45:28

Also I am curious to what you guys use for brushed metal? do you use a high IOR or low?

Title: Re: Caustics, refraction, glass questions.
Post by: Jahman on 2013-03-10, 23:54:06

high ior + a bit of reflection gloss randomness + brushed bump map + right mult of anisotropy
brushed steel = steel so material ior (reflectance) mostly constant.
my test in attachment

Title: Re: Caustics, refraction, glass questions.
Post by: ecximer on 2013-03-11, 09:42:48

Jahman, can you show me wire?

Title: Re: Caustics, refraction, glass questions.
Post by: Jahman on 2013-03-11, 09:56:39

Ecximer, I'll post the result in a new topic some time later
there's my previous steel test. sorry for the img size

Title: Re: Caustics, refraction, glass questions.
Post by: ecximer on 2013-03-11, 10:01:56

0_o
Very high quality stuff out - well done!
Hdri can share?

Title: Re: Caustics, refraction, glass questions.
Post by: AnubisMe on 2013-03-12, 02:24:31

Okay, I made some progress. I am still having a hard time getting the glass just right, but even more so I am not sure how I can give the illusion that their is a yellow perfume liquid inside. The Absorption is giving me really strange results when I try it.

Title: Re: Caustics, refraction, glass questions.
Post by: Polymax on 2013-03-12, 19:17:40

I try and result (only hdri):

Title: Re: Caustics, refraction, glass questions.
Post by: AnubisMe on 2013-03-12, 21:12:24

Do you mind sharing the scene with me? you seem to have got the liquid part down prety good!

Title: Re: Caustics, refraction, glass questions.
Post by: ecximer on 2013-03-13, 07:21:44

No bad, no bad, Maxim :)
Continue to surprise us!

Title: Re: Caustics, refraction, glass questions.
Post by: Polymax on 2013-03-13, 10:00:03

Thanks!
Little fix. And scene:
Add the scene in 2011 max format.