Glass turns invisible / doesn't get rendered

I have a strange problem. I was modeling my characters eye tearline and i noticed the shader turns that eyes part underneath invisible. So i set up a plane with solidify modifier and the tearline material to test and it turns out looking through that glass makes the eye invisible.
Then i was curious if my shader is just bad but simple Principled shader with transmission set to 1 on both meshes looking the same.
I’ve done this like a hundred times the same before and even in my Portraits i posted here i’ve done it this way.
I really have no idea what causes this.
Testet on the official 2.9 release and downwards to 2.8 releases rendered with optix, cuda and just cpu everywhere its the same problem.




Can you send both materials in a separate file?

I’m going to guess the tracing depth is not high enough somewhere in the render settings. This one extra transparency makes it too high.

GlassProblem.blend (3.6 MB)

with a low tracing depth the shader just turns black with reflections. But in this case the transparent shader turns completly invisible/ doesnt get rendered at all. I’ve double checked all the settings but couldnt find anything unusual

image problem should dissapear when you turn on transmission rays in Ray visibility settings of the eyeball

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That worked
oh my gosh i’m so stupid. I cant remember tuning that even off.
Thank you very much

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