Glass does not look transparent

[Zvi]

In the attached images you can see that the glass in the front of the bottle does not look like a transparent glass, but frosted. I used full raybouncing, dielectric material with the correct definitions, and good lighting.

[Zvi]

I'm attaching the file of the scene itself, if someone wants to check it.

[Esben Oxholm]

Hi Zvi.

I had a quick look at it. I think it comes down to two factors:

1. Lighting:
Your HDRI is kinda contrastless and is especially lacking dark areas. Try using a HDRI with higher contrast and fully black areas.

2. Model and material setup:
Accurate representation of liquid inside glass containers needs a bit of (not so obvious) setup work.
You should in your CAD software split the surfaces as sketched in the attached image. The left part shows how your setup is a the moment (as far as I could see) and the right shows the ideal setup.

All three surfaces should have the dielectric material applied and be adjusted as this:
(Quoted from Dries (except from color references) from https://www.keyshot.com/forum/index.php?topic=12499.0 - Not sure why I didn't just link to this from the beginning)

Orange surface: Dielectric material. Refraction Index = 1.5 (or whatever is appropriate for your bottle's material)
Blue surface: Dielectric material. Refraction Index = 1.334 (the IOR of the liquid) / Refraction Index Outside = 1.5 (the IOR of the bottle)
Green surface: Dielectric material. Refraction Index = 1.334 (the IOR of the liquid) / Refraction Index Outside = 1 (the IOR of air)

Hope it helps.

[DMerz III]

Esben, I have to draw that exact sketch out for my CAD designers every time we render some kind of glass bottle, haha.

[richardfunnell]

Haha, yep, saved for future use! Thanks