Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: pavel2405 on 2014-09-26, 22:41:51

Title: Not work caustic render in Corona v.7.1
Post by: pavel2405 on 2014-09-26, 22:41:51

Guys, who know how to do caustics in corona render v7.1? I want do this (http://img190.imageshack.us/img190/6205/causticstest.jpg)
I have this (http://pikbox.ru/img/19/20140928040722966_4.jpg)
this's my sheder (http://pikbox.ru/img/10/20140928040607772_1.jpg)

Title: Re: Not work caustic render in Corona v.7.1
Post by: Ondra on 2014-09-26, 22:50:12

change render engine from progressive to bidir/VCM

Title: Re: Not work caustic render in Corona v.7.1
Post by: pavel2405 on 2014-09-26, 23:08:43

not work bidir/VCM (http://pikbox.ru/img/11/20140928042911276_7.jpg)

Title: Re: Not work caustic render in Corona v.7.1
Post by: Ondra on 2014-09-26, 23:31:24

this should work, are you using displacement? Try playing with the displacement height (increasing it)

Title: Re: Not work caustic render in Corona v.7.1
Post by: romullus on 2014-09-26, 23:35:45

Does single plane have to produce caustics? I think it must have some thickness for that. Sorry if i'm wrong.

Title: Re: Not work caustic render in Corona v.7.1
Post by: pavel2405 on 2014-09-27, 00:25:19

I ge t caustic effect by adding displacement. But it does not looks realistic. extruding the plane didn't make the effect better.
(http://pikbox.ru/img/18/20140928054712547_9.jpg)
https://forum.corona-renderer.com/index.php?topic=923.0
i would like to repeat this effect in corona render?

Title: Re: Not work caustic render in Corona v.7.1
Post by: juang3d on 2014-09-27, 00:54:02

In fact you get pretty realistic caustics, the problem may be the render time needed to clean it up.

In your case I bet you have a diffuse light source like a big area light, this will give you what you show, blurred caustics, for sharp caustics you need a sharp source of light, like the sun or a point (or nearly point) light.

Check attached picture and scene.

Cheers!

Title: Re: Not work caustic render in Corona v.7.1
Post by: pavel2405 on 2014-09-27, 01:47:22

Quote from: juang3d on 2014-09-27, 00:54:02

In fact you get pretty realistic caustics, the problem may be the render time needed to clean it up.

In your case I bet you have a diffuse light source like a big area light, this will give you what you show, blurred caustics, for sharp caustics you need a sharp source of light, like the sun or a point (or nearly point) light.
Сould you gme scene in
Check attached picture and scene.

Cheers!

Its really works. Problem was in geometry and light (i had plane light)

Thanks guys for your quick reply. You have helped a lot. Rendering its magic!!!))
(http://pikbox.ru/img/21/20140928070444723_45.jpg)

Title: Re: Not work caustic render in Corona v.7.1
Post by: naikku on 2014-09-27, 10:13:27

I want to say that I have never tried to do caustics in Corona, Juang3Ds rendering looks guite nice and that has been rendered fast :)
I did try before with Mental Ray and it took ages to finish an image. I too have to try caustics now :)

But in Pavels latest image, there is some fireflies on the water surface?

Title: Re: Not work caustic render in Corona v.7.1
Post by: juang3d on 2014-09-27, 10:25:10

In my max I'm not using the default Bidirectional engine, in the bidir section of the engine you have a rollout with several options, I tried it all and I picked the one the I found with less fireflies and good result.
Pavel is probably using the default one, it generates those fireflies in the water surface, I'm not sure if they will go with time (probably), but for this test I picked a different one (I don't remember the name right now)

Cheers.

Title: Re: Not work caustic render in Corona v.7.1
Post by: Ondra on 2014-09-27, 10:51:27

switch the mode to VCM to get rid of those fireflies.

Title: Re: Not work caustic render in Corona v.7.1
Post by: pavel2405 on 2014-09-27, 16:07:43

Quote from: Keymaster on 2014-09-27, 10:51:27

switch the mode to VCM to get rid of those fireflies.

VCM mode works, but not very good(

Title: Re: Not work caustic render in Corona v.7.1
Post by: elnino on 2014-09-29, 12:26:21

Hi,
I made a similar test in Blender + Corona Standalone and noticed a strange behaviour.
When using VCM the render stopped after 178 passes. Nothing change on the render anymore even if rays stats continue increasing. The computer also stop processing.

(http://www.pasteall.org/pic/show.php?id=77861)

Title: Re: Not work caustic render in Corona v.7.1
Post by: juang3d on 2014-09-29, 12:41:00

Have you tried the other engines to see if you get better results with them?

Cheers.

Title: Re: Not work caustic render in Corona v.7.1
Post by: maru on 2014-09-29, 12:50:53

I guess this is what is happens when you are using experimental features.

Title: Re: Not work caustic render in Corona v.7.1
Post by: elnino on 2014-09-29, 13:40:52

I think too, just wanted to mention the behaviour.
Progressive works fine, but caustics are bad. The same problem appears with progressive photon mapping. So it's due to those rendering types being experimental features.

Title: Re: Not work caustic render in Corona v.7.1
Post by: naikku on 2014-09-29, 14:51:48

My first attempt to create caustics with Corona. Seems to me Bidir/VCM and VCM from the dropdown-list seem to work the best, at least for me.
Facinating, made a small animation and I will leave it to be rendered to our renderfarm.