Corona Renderer Forum

General Category => Feature requests => Resolved feature requests => Topic started by: cecofuli on 2013-07-01, 11:44:13

Title: Dispersion shader
Post by: cecofuli on 2013-07-01, 11:44:13
As in the title, a dispersion features for realistic diamond and glasses. Thanks!

(http://www.3dworldmag.com/files/2011/03/TDW141.r_vray.basicglass.jpg)
Title: Re: Dispersion shader
Post by: cecofuli on 2013-07-01, 16:12:22
This was the good old fake method with VRay.

(http://members.home.nl/dezwart/test/crystal-settings.png)

(http://members.home.nl/dezwart/test/crystal.jpg)
Title: Re: Dispersion shader
Post by: APrather on 2013-07-01, 16:53:00
It was asked before http://corona-renderer.com/forum/index.php/topic,311.0.html  B

BTW Nice Vray dispersion you got there.
Title: Re: Dispersion shader
Post by: maru on 2013-07-01, 17:05:53
here is my fake dispersion done in Corona :]

http://corona-renderer.com/forum/index.php?action=dlattach;topic=223.0;attach=1887;image
Title: Re: Dispersion shader
Post by: cecofuli on 2013-07-01, 17:45:20
Maru... how did  you do that? It look not bad at all.
Title: Re: Dispersion shader
Post by: cecofuli on 2013-07-01, 17:52:15
This is my Corona render. The diamond looks looks like a normal glass :/

(http://www.francescolegrenzi.com/Temp/150_Test_WHYTE.jpg)
Title: Re: Dispersion shader
Post by: maru on 2013-07-01, 18:18:11
Basically it's done like your vray fake. Here are the instructions. It's dirty and ugly but more or less does its job.
Title: Re: Dispersion shader
Post by: cecofuli on 2013-07-01, 18:41:13
Ok I tried, but the diamond becomes dark with this shader.
I think we have to wait Ondra...  =(
Title: Re: Dispersion shader
Post by: maru on 2013-07-01, 19:01:56
Yeah, the colours should mix in a different way. And something is wrong with the blend material.
Title: Re: Dispersion shader
Post by: cecofuli on 2013-07-01, 19:15:21
We have to wait a new CoronaBlendMtl ;-)  and/or dispersion option in the CoronaMtl.
Title: Re: Dispersion shader
Post by: Chakib on 2013-07-04, 02:26:51
i hope we can see it soon cause the glass in corona is just amazing even without caustics...
Title: Re: Dispersion shader
Post by: lacilaci on 2013-07-04, 13:49:11
Well dispersion was mentioned before. If I remember correctly, Ondra said, it will be done. But right now it's not a top priority to do... Which is understandable i think.
Title: Re: Dispersion shader
Post by: cecofuli on 2013-07-04, 14:17:07
Yes, but, for example, with VRay was possible create a "fake dispersion". And, for some project, it's enough.
I have to use VRay for our next project cause Corona doesn't support dispersion. It's important when you are working with jewelry ;-)
Title: Re: Dispersion shader
Post by: cecofuli on 2013-08-07, 18:51:26
UP =)
Title: Re: Dispersion shader
Post by: borisquezadaa on 2014-03-18, 01:59:18
Playing with diamonds...

i just came up with this aproach to fake dispersion:

Diamond has a ior of 2.418 and a dispersion of 0.044 (wikipedia) XD.

So i created 3 materials one with IOR 2.374, one with IOR 2.418 and one with IOR 2.462

Apply first material (ior 2.374) and render, saving only the red channel (in post tab).
Then apply second material (ior 2.418) and render only saving green channel.
Finally apply third material (IOR 2.462) and render only saving blue channel.

Load that 3 images in photoshop seting layer as addittive and get nice FAKE dispersion.

Pretty nice trick. And Eureka moment.
Title: Re: Dispersion shader
Post by: Nekrobul on 2014-03-24, 12:19:26
Well i have tried one method too similar to v-ray fake method but i little more dificult.

I used 3 blend materials with 4 different materials inside and 3 fallof maps to mixthem together.

in close up it still looks un realistik but from the distance gives needed effect.
Title: Re: Dispersion shader
Post by: agentdark45 on 2014-03-24, 13:07:11
Hi Nekrobul would you mind uploading your material for testing? I've currently doing a project with some crystal wall sconces and can't quite nail the look (currently using a regular glass material with caustics ticked, ior 2.0 for both ref+refract).

Many thanks

Title: Re: Dispersion shader
Post by: Nekrobul on 2014-03-24, 13:12:34
Only in couple of hours or later, need to do some urgent work now)
Title: Re: Dispersion shader
Post by: agentdark45 on 2014-03-24, 14:22:45
Thanks man
Title: Re: Dispersion shader
Post by: borisquezadaa on 2014-03-24, 15:19:14
You may try with this way of doing...
http://corona-renderer.com/forum/index.php/topic,3093.0.html

Only thing is to change refraction (For a SiO type glass...)]

658nm=1.5418
510nm=1.54812
440nm=1.55339
Title: Re: Dispersion shader
Post by: XRef on 2015-03-10, 19:28:41
Is there any new info on rendering diamonds? I made an attempt similar to cecofuli's render...

Title: Re: Dispersion shader
Post by: cecofuli on 2015-03-10, 19:36:06
We need to wait dispersion. I hope soon (Ondra? ^__^ )
Title: Re: Dispersion shader
Post by: tomislavn on 2015-05-29, 12:41:24
Any news on dispersion option Ondra? :)
Title: Re: Dispersion shader
Post by: mitviz on 2015-06-05, 21:57:19
bump for this request!i need it so badly
Title: Re: Dispersion shader
Post by: Tanakov on 2016-04-18, 11:30:40
Bumpy :)
Title: Re: Dispersion shader
Post by: maru on 2016-04-18, 14:03:17
Democratic Republic of Corona encourages you to vote: https://corona-renderer.com/forum/index.php/topic,96.msg73352.html#msg73352