The Geometrical Optics (gop) interface (), found under the Optics>Ray Optics branch () when adding a physics interface, computes the paths of electromagnetic waves in the high frequency limit. The wavefronts are treated as rays that can propagate through optically large geometries and reflect or refract at boundaries. The Geometrical Optics interface includes built-in options to compute the ray intensity, polarization, phase, and optical path length. It is also fully compatible with deformed geometries such as systems with thermal stress.

When this physics interface is added, these default nodes are also added to the Model Builder: Medium Properties, Material Discontinuity, and Ray Properties. Then, from the Physics toolbar, add other nodes that implement, for example, light sources or boundary conditions. You can also right-click Geometrical Optics to select physics features from the context menu.