Author Topic: Double reflections on glass  (Read 2275 times)

2018-06-21, 12:05:01

Andrew_G

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Hello there:)

I`m just trying to move from vray to Corona, but I stucked with this strange glass problem. I have some bottles that I need to render. Light setup is straight forward:
back light with some gradient
strong left light with gradient
right weaker light with some gradient

And there goes my bottles with very strange double reflections, that looks very weird. Can you give me a hint, what to do to make this glass look more clear?
I want to put inside this bottles some liquid, but when I do that, number of reflections increases and all is looking more and more strange...


2018-06-21, 12:35:44
Reply #1

Nejc Kilar

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Not sure if this is going to help you but are you making sure your liquid intersects with the glass? https://coronarenderer.freshdesk.com/support/solutions/articles/5000515618-how-to-model-a-liquid-in-glass-in-corona-

Also, in V-Ray you need to enable "reflect on back side" in order to see the reflections on the inner side of the bottle. It is disabled by default but its more "correct" to have it enabled.

2018-06-21, 12:37:01
Reply #2

Andrew_G

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Yes, yes. That was teh first thing I checked:)

2018-06-21, 13:19:25
Reply #3

Nejc Kilar

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Hmm, are the normals pointing in the right directions too?

2018-06-21, 13:30:20
Reply #4

Andrew_G

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Yes, yes they are. Unfortunately, because I cant find any more obvoius problems, and these strange reflections are still there...

2018-06-21, 14:15:15
Reply #5

beanzvision

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Firstly, there is no need to activate the diffuse channel for glass. Corona will render just fine without it. As for the double reflection, Is this not how it would be in real life?
« Last Edit: 2018-06-21, 17:34:26 by beanzvision »

2018-06-21, 16:31:41
Reply #6

Andrew_G

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Quote
Firstly, there is no need to activate the diffuse channel for glass. Corona will render just fine without it. As for the double reflection, Is this not how it would be in real life?

Thank you. It looks quite ok, but if you will remove absorption from liquid (as for example in mineral water), those ugly reflection will start to show up. I noticed that absorption with colour is reducing all this reflections, but without any volumetrics it will start looking as in my pictures.

2018-06-21, 16:35:43
Reply #7

houska

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I think double reflections are perfectly natural...

2018-06-21, 17:32:59
Reply #8

beanzvision

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This is another one without volumetric water, just refraction no reflection.

2018-06-22, 08:15:32
Reply #9

Andrew_G

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Thanks you guys for help. I tweaked this bottle a little, and I managed to get more or less good results. It turns out that turning on caustics and adding some absorption should make glass materials a lot better... a bit slower tough, but as for my first glass object in corona, I`m quite happy with the result:)

2018-06-22, 16:07:47
Reply #10

hdri3d

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hi very nice result you can make available the c4d file of the scene so the community can enjoy the result thanks

2018-06-22, 19:04:04
Reply #11

Eddoron

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Seems like your liquid doesn't penetrate the glass.

2018-06-28, 14:15:14
Reply #12

maru

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Internal reflections are actually accurate. In V-Ray (at least some older versions), this option is disabled by default.

2020-04-03, 18:17:29
Reply #13

NOOKTA

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Hi guys,

I know this is an older thread but it actually is exactly what I need help with right now.

I'm looking to create a glass panel, that also shows reflections on the backside (as in Vray checkbox). I'm attaching some snapshots and a scene of my current setup, without the HDRI (too big). Some notes for the snapshots:

  • left selection is two planes / 2cm offset / normals outwards
  • middle selection is two planes / 2cm offset / normals same direction, towards camera
  • right selection is box/sheet of glass, no flipped normals

Material is created from scratch, disabled diffuse and only checked/unchecked the "thin (no refraction)" checkbox.

What I want is to see reflections on backsides, so the reflection of any second plane/box should be a little offset, right?

I'm also attaching the Vray example. And I already checked this link: https://coronarenderer.freshdesk.com/support/solutions/articles/5000515622-how-to-set-up-realistic-glass-metal-materials

I hope you understand and can help me with this!

Corona Version: 5.0
Cinema version: R21.207 Cinema 4D (single-license)

Best,

Ararat

www.nookta.de — architectural visualization based in germany
https://www.instagram.com/nookta_visualization/

2020-04-04, 20:34:22
Reply #14

ficdogg

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Are the planes connected in a single "pane" or just one behind the other?
In this render you'll see with two planes one behind the other you get a single reflection, while with the "pane"(cube primitve) you get the double reflection. Same distance in both cases.