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.

The scene can be downloaded here.

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

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: