How can I render an empty transparent glass cup more realistically in Isaac Sim?

Omniverse Isaac Sim
1

γ‚Ήγ‚―γƒͺγƒΌγƒ³γ‚·γƒ§γƒƒγƒˆ 2026-07-14 183722
γ‚Ήγ‚―γƒͺγƒΌγƒ³γ‚·γƒ§γƒƒγƒˆ 2026-07-14 183722657Γ—508 41.8 KB

Hello,

I am generating synthetic images of transparent glass cups in Isaac Sim.

I placed an image plane behind an empty glass cup to check how the background is refracted through the cup. However, as shown in the attached image, the background letters are strongly distorted and partially inverted through the cup.

I understand that refraction can distort the background, but compared with a real empty glass cup, the distortion and inversion seem too strong.

My current settings are as follows:

Renderer: RTX Interactive / Path Tracing
Material: OmniGlass / Refraction Glass
IOR: around 1.1–1.3
Cup: hollow mesh with thickness
Thickness: around 0.1–0.2 scene units
Background: image plane placed behind the cup

What I would like to achieve is:

  • An empty transparent glass cup
  • The background visible through the cup
  • Natural refraction similar to a real glass cup
  • Less excessive inversion and distortion

Could anyone give me advice on the following points?

  1. Are there recommended material settings for rendering an empty glass cup?
  2. Should I use thin_walled = True, or should I model the cup as a mesh with real thickness?
  3. What values are appropriate for IOR / roughness / opacity for this kind of transparent object?
  4. Are there any recommended RTX Path Tracing settings for transparent objects?
  5. Is this strong inversion mainly caused by the cup geometry, material settings, surface normals, or renderer settings?

Any advice on how to make the transparent cup look more realistic would be appreciated.

Thank you.

3

Hi @23ef025, could you please verify what is the meters per unit in your setup? By default, it is 1 meter. So 0.1-0.2 scene units is about 10, 20 cm. This is pretty thick for a glass cup.

Use thin_walled=false for a real hollow mesh with inner and outer walls. Use thin_walled=true only for a single-surface thin-shell cup.

For IOR for glass, could you please try values 1.45-1.52? Only lower IOR as an artistic compromise if the goal is label/background legibility rather than physical realism. Keep clear-glass roughness low, for example frosting_roughness near 0.0 to 0.02. Avoid cutout/opacity tricks for physical clear glass; control tint/absorption with the glass color and depth/absorption parameters.

Prefer PathTracing for final synthetic data involving transparent cups. Raise specular/transmission bounces to about 12 to 16 and use higher samples, for example 64 to 256 spp, for final captures.

4

Thank you for the detailed advice.

I realized that I may have misunderstood the scene unit scale. I was using 0.1–0.2 scene units as the cup thickness, but if the stage meters per unit is 1.0, that corresponds to 10–20 cm, which is much thicker than a real glass cup.

I will first check the stage meters per unit and rescale the cup to real-world dimensions, for example around 0.118 m height and 0.001–0.003 m wall thickness.

I will also try thin_walled=false with a real hollow mesh, IOR 1.45–1.52, roughness around 0.0–0.02, and avoid using opacity as a transparency trick. For final rendering, I will use Path Tracing with higher transmission/specular bounces and higher samples.

Thank you again. I will test these settings and compare the results.