Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Christa Noel on 2014-09-27, 05:09:24

Title: need to create realistic glass, but how??
Post by: Christa Noel on 2014-09-27, 05:09:24
Dear all,
i want to create realistic glass like the pictures i attached (photo). how to setup the glass material with green color on the edge and clear on the surface? do i have to create multimaterial, clear for the surface & green for the edge..?? need advise please :-)

thanx!
Title: Re: need to create realistic glass, but how??
Post by: maru on 2014-09-27, 09:55:27
Start with creating a standard transparent glass and giving it greenish absorption colour.
Title: Re: need to create realistic glass, but how??
Post by: crazyman on 2014-10-03, 12:03:41
As maru correctly suggest, add absorption color and some distance value. Start with 1-2cm distance and 205,225,220 RGB as color value. Adjust accordingly.
Title: Re: need to create realistic glass, but how??
Post by: Christa Noel on 2014-10-03, 13:48:05
Sorry for delayed reply..
now i'm still trying & trying to create the best flat glass material setup.
But Thanx very much Crazyman & Maru for great advises
Title: Re: need to create realistic glass, but how??
Post by: Cyanhide on 2014-10-03, 17:21:14
Or you can cheat and select your border give it another ID and use a green glass for the borders :)

That's cheating though,
Title: Re: need to create realistic glass, but how??
Post by: maru on 2014-10-03, 17:29:41
Or you can cheat and select your border give it another ID and use a green glass for the borders :)

That's cheating though,
I'm not sure if mixing 2 glass materials on different faces of one object won't cause strange refractions.
Title: Re: need to create realistic glass, but how??
Post by: Cyanhide on 2014-10-03, 17:34:08
Or you can cheat and select your border give it another ID and use a green glass for the borders :)

That's cheating though,
I'm not sure if mixing 2 glass materials on different faces of one object won't cause strange refractions.

Tbh, I wouldn't know haven't done this myself, but I remember a similar question on CGarchtitect forum and a member posted this answer, I was baffled by the simplicity. It worked for Vray so I'm not sure why It wouldn't work with Corona? If you use the same material but apart from the color why would this do anything to the refraction?  :D
Title: Re: need to create realistic glass, but how??
Post by: agentdark45 on 2014-10-03, 17:47:48
I think 2 materials might be the way to go.

When you examine the edge of cut and finished glass (like in your photo), the edge faces are often have very blurred dull reflections / refractions.
Title: Re: need to create realistic glass, but how??
Post by: Image Box Studios on 2014-10-04, 11:17:02
Hi....Cheers..
Title: Re: need to create realistic glass, but how??
Post by: maru on 2014-10-04, 11:59:00
Or you can cheat and select your border give it another ID and use a green glass for the borders :)

That's cheating though,
I'm not sure if mixing 2 glass materials on different faces of one object won't cause strange refractions.

Tbh, I wouldn't know haven't done this myself, but I remember a similar question on CGarchtitect forum and a member posted this answer, I was baffled by the simplicity. It worked for Vray so I'm not sure why It wouldn't work with Corona? If you use the same material but apart from the color why would this do anything to the refraction?  :D
This is what happens when you use two refractive materials on an object with two material IDs. Corona is not Vray. :)
Left: one material with absorption
Right: two materials on different faces, one pure glass (top and bottom), one greenish glass (edges). It just looks wrong and works wrong. You can even check by assigning THE SAME glass material to different faces with different material IDs, refraction will look wrong. Keymaster once explained this, I don't remember but I would guess it has something to do with Corona not being able to tell what is the "volume" of such object so it treats it like two objects with no thickness. 
Title: Re: need to create realistic glass, but how??
Post by: Christa Noel on 2014-10-23, 05:29:57
after several time in researching and asked some friends, i think i got the right answer.
Maru is totally right, we cannot use two materials ID (for the edges & the top/bottom). i rendered these 2 glass material with corona & vray, and the result is as the same as i thought. the refraction won't look like real glass, right result is mean with the very very thin edge (jst like have no thickness) on the far side of the edge when we look a bit straight from the other edge (see attached photos).
Crazyman & Maru has the right answer for this, use bright greenish with low saturation & 5-20mm depth absorption.

But after finished this project, i got another problem. the render result look so noisy, i've spent 14hrs rendertime with distributed rendering (mainPC: i5 4570 win7 RAM4G RadeonR7-200 & slavePC: i7 4770 win7 RAM4G RadeonR7-200) .. i don't know why. i'm still very rookie with this magical renderengine. i've change the rendersetup many times but no clear & smooth result (i've changed this= "max samples intensity: 0,10,20" , "GI/AA balance:16,32,64"), that noises was so scared me. need more advises please..

thanx corona!
Title: Re: need to create realistic glass, but how??
Post by: Chakib on 2014-10-23, 15:03:30
Why 14h for this scene?? :/
Title: Re: need to create realistic glass, but how??
Post by: maru on 2014-10-23, 17:04:04
Light samples multiplier: 16
Max sample intensity: 0
hd cache precomp density: 32
recor quality 8000

WHAAAAAAAAAAAAT :D

Reset all settings to default, it should render MUCH faster. Also, show us glass settings, it may cause troubles, especially with light.
Title: Re: need to create realistic glass, but how??
Post by: Christa Noel on 2014-10-24, 08:10:31
yes maru, i already tried the default rendersetup.. but it produced too much noise. then i tried to change the setup to tweak the quality. but yesterday i read corona performancedebugging, now i'm still trying to really really understand what the noise problem is.
here attached images are the materials setup.

thanx!
Title: Re: need to create realistic glass, but how??
Post by: maru on 2014-10-24, 09:52:52
Are you using IES light?
Title: Re: need to create realistic glass, but how??
Post by: Christa Noel on 2014-10-24, 11:51:29
no, ies at all. check attached images
Title: Re: need to create realistic glass, but how??
Post by: maru on 2014-10-24, 12:04:01
Light inside the cabin - how did you make it?

Does the noise go away after you, for example, disable some lights, hide some objects (like glass panels)?
Title: Re: need to create realistic glass, but how??
Post by: Christa Noel on 2014-10-27, 08:31:45
i just use lamp-case inside the cabinet that looks glow a bit.. and i don't need to light the cabin inside.

But anyway this problem is being resolved
- background diffuse color is changed to 180,180,180
- rendersetup is reseted to default
- disabled caustic material on the glass lamp-case inside the cabin
i do changes on my another item (similar). the noises is so much reduced, but they're still there a bit and the accuracy isn't good enough (next chance, i'll try to fix it with expanding the rendertime).
then i have another question according to "https://corona-renderer.com/wiki/performance_debugging".  Do i have to change the corona light color to 180??

thanx again Maru!!
Title: Re: need to create realistic glass, but how??
Post by: maru on 2014-10-27, 12:11:31
I think it's a bug (sampling issue?). Already reported this and waiting for answers...