The reflection and refraction of Arnold glass material is wrong

[2497373304]

  Hi guys. I have been learning Arnold recently and encountered some problems when making glass materials.
  When rendering transparent products with thickness, Arnold will have an extra layer of reflection compared to other renderers. Normally it should be two layers, but in Arnold there will be a three layer effect.
  I tried adding the Arnold tag, as well as changing the internal reflection in the material. The result is still wrong. I found that when the "Transparency Depth" in the render settings is 0, the reflection results obtained are correct. But this transparent material will turn black.
  I uploaded the project and pictures，Do you guys have any solutions?

 

 

[2497373304]

@lee_griggs

Boss, do you know how to solve it?

[2497373304]

@Stephen.Blair 

Boss, do you know how to solve it?

[wernienst]

I don't see 3 reflections. I do see 2 overlapping reflections: one from the outer surface of the bottle, one from the inner - the internal reflection.

Since I don't have Arnold for Cinema4D, I tried to recreate your scene in 3dsMax. It looks like this:

If I deactivate Internal Reflections, I get this:

Here are my Standard Surface settings:

[2497373304]

Thanks for your reply, man! Just like in your first picture, you will see that there are three layers of refraction and reflection, and the outermost layer is far away from the second layer. Because I often take photos of this transparent water cup, I know that this is not the case under normal circumstances. Of course, you can also use other renderers for comparison, and the results you get will still not be like Arnold!

[CiroCardoso3v]

You can also use the option Thin Walled

[wernienst · Accepted solution]

I have to admit: you are right!

I have thickened the bottle wall and colorized the glass. Now it's obvious.

We have the white (blurry) reflection of the light, the reflection of the light shape (sharp edges) and then the third blurry reflection - of what?

If I uncheck Light Shape Visible I get this:

It's way larger then the other reflections, so it's maybe the refracted specular light, reflected by the inner surface back to the outer surface and refracted from there into the scene. That's not correct but that's how it works...

If you want correct reflections you have to use mesh lights like here:

[2497373304]

Thank you bro, using mesh lights is a good solution. I've been obsessed with tweaking materials and settings. Thanks again

[2497373304]

The official developers tell me this is a known bug https://forums.autodesk.com/t5/arnold-for-cinema-4d-forum/the-reflection-and-refraction-of-arnold-gl...