Use the Library > Rendergraph > Presets > Glass preset from the library to render convincing glass objects. This preset uses the Surface shader and override specific parameters to avoid classic caveats.

4 bounces refraction on a hollow glass.

By default, the Glass preset forces a 4 bounces refraction so it is easy to render a transparent glass. You can easily change this to a 2 bounces refraction by modifying the following attributes:

  • Shader > Spec1 > Ray Depth = 2
  • Shader > Glass > Ray Depth = 2
  • Attributes > Raytracing > Max Bounces = 1

The Max Bounces value makes sure the glass object won't be traced any more after 1 bounce.

The Stanford Armadillo rendered with 2 bounces, and with 4 bounces. The Library/Materials/Surface shader for details.