Rendering Glass Surfaces with Arnold

There are some common problems faced when rendering refractive glass surfaces with Arnold. There are a few guidelines that need to be followed when modeling surfaces where there is a liquid to glass interface. The problem lies in how the renderer determines if we are entering or exiting an object, and what the incoming and outcoming interfaces are.

The standard_surface shader assumes outward facing normals, that objects are embedded in air, and that there is no overlapping between them.

We will demonstrate the results obtained from the various modeling approaches below:

• The liquid and container touch exactly.
• The liquid and container have a gap between them and therefore do not touch each other.
• The liquid and container overlap each other.
• We will also cover what material and render settings to use when rendering glass surfaces.

The tutorial is presented in the three following sections:

• Modeling Glass and Liquid
• Shading Glass and Liquid
• Render Settings

A tutorial that shows tips on shading a plastic water bottle can be found here.