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Thickness and refraction

Stan NiceStan Nice Posts: 25
in Technical Help (nuts n bolts)

Hello,

I would like to create a material that turns objects into glass. But The way I configure it with Iray Uber is wrong and I don't know why.

I would like the light not to go through the object uniformly, but as you can see on the picture, the light renders the same way everywhere on the sphere. On its center, it should appear more "thick", let pass less light. And it's not. I can't find more explanation on the web (despite this masterpiec :http://docs.daz3d.com/lib/exe/fetch.php/public/read_me/index/38627/38627_master-reference-uber-shader-reference-guide.pdf) .

Picture of the sphere problem :

https://ibb.co/FKqRYmh

Can you tell me which parameter should influence the light depending of the object thickness ?

What i used :

Gloss reflectivity :1

Glossy roughness :0.1

Refraction weight : 0.7

Cutout opacity : 0.7

Everything else is set to default Iray Uber.

 

Thank you!

 

Comments

  • LeanaLeana Posts: 11,783

    Try setting "thin walled" to off if it's on.

  • Stan NiceStan Nice Posts: 25
    edited November 27

    Thin walled OFF didn't changed anything. i tried to change the value of "transmitted measurement distance" but it didn't changed anything too. I don't understand how this works...

    Post edited by Stan Nice on
  • crosswindcrosswind Posts: 7,268

    Tweaking values in Refraction Index, Abbe, and/or adding some Metallic Flakes Weight, texture map into Refraction Color slot, etc., can give it "thickness" effect that'll affect refraction and transmission of lights.

    Or use some Glass shader products.

  • Richard HaseltineRichard Haseltine Posts: 101,443

    Have you tried one of the dispersive shader presets? Is it the view through the obejct or light transmitted through the object onto the surfaces behind that you are after?

  • Stan NiceStan Nice Posts: 25

    crosswind said:

    Tweaking values in Refraction Index, Abbe, and/or adding some Metallic Flakes Weight, texture map into Refraction Color slot, etc., can give it "thickness" effect that'll affect refraction and transmission of lights.

    Or use some Glass shader products.

    Yes I tried (not for metallic though) and if I get a thickness effect, it never applies it the way it should. Sorry english isn't my mothertongue so maybe I'm not clear with my explanations. 

    The more the object is thick, the less the light should pass trough and the more we should have a "cloudy" or "glassy" effect. So looking at the sphere, there should be a gradient from the border to the center, making it look-like 3d and not 2d. Instead, it looks like the render engine consider the whole as one 2d disc surface hence light passing through it looks exactly the same whatever we have 10cm or 1meter of matter's thickness.

  • Stan NiceStan Nice Posts: 25

    Richard Haseltine said:

    Have you tried one of the dispersive shader presets? Is it the view through the obejct or light transmitted through the object onto the surfaces behind that you are after?

    I have to say that I didn't thought about default iray shaders as the most part of the time I need new ones. But I will try them and play a bit with, thanks !

  • crosswindcrosswind Posts: 7,268

    Stan Nice said:

    crosswind said:

    Tweaking values in Refraction Index, Abbe, and/or adding some Metallic Flakes Weight, texture map into Refraction Color slot, etc., can give it "thickness" effect that'll affect refraction and transmission of lights.

    Or use some Glass shader products.

    Yes I tried (not for metallic though) and if I get a thickness effect, it never applies it the way it should. Sorry english isn't my mothertongue so maybe I'm not clear with my explanations. 

    The more the object is thick, the less the light should pass trough and the more we should have a "cloudy" or "glassy" effect. So looking at the sphere, there should be a gradient from the border to the center, making it look-like 3d and not 2d. Instead, it looks like the render engine consider the whole as one 2d disc surface hence light passing through it looks exactly the same whatever we have 10cm or 1meter of matter's thickness.

    The 1st screenshot is an ordinary glass shader... the 2nd screenshot is the tweaked one with some "thickness" effect. 

    SNAG-2024-11-29-000.png
    2560 x 1440 - 3M
    SNAG-2024-11-29-001.png
    2560 x 1440 - 4M
  • richardandtracyrichardandtracy Posts: 5,738
    edited November 29

    I used the Uber shader for my glass prop freebies here: https://www.daz3d.com/forums/discussion/549566/decorative-norwegian-glass-props

    You could use those settings as a start. The refraction in the stem of the glass on the left surprised me. The red & yellow lines are a constant diameter helix and only the Index of Refraction (IOR) is causing them to seem to change size.

    One thing I did notice is that glass really works best when there is a front and a back facet defining an 'inside', I couldn't get the 'Thin Walled' effects to work, so it's off.

    Regards,

    Richard

    Post edited by richardandtracy on
  • Richard HaseltineRichard Haseltine Posts: 101,443

    richardandtracy said:

    I used the Uber shader for my glass prop freebies here: https://www.daz3d.com/forums/discussion/549566/decorative-norwegian-glass-props

    You could use those settings as a start. The refraction in the stem of the glass on the left surprised me. The red & yellow lines are a constant diameter helix and only the Index of Refraction (IOR) is causing them to seem to change size.

    One thing I did notice is that glass really works best when there is a front and a back facet defining an 'inside', I couldn't get the 'Thin Walled' effects to work, so it's off.

    Regards,

    Richard

    Thin walled is precisely for those cases where there isn't a volume, so it cannot do internal effects or refract entering and leaving.

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