The Exterior Field Calculation feature adds the equations necessary to postprocess the exterior field to the computational domain for open problems. The feature is the same as the Exterior Field Calculation in The Pressure Acoustics, Frequency Domain Interface. This feature will only generate variables and results that can be used in postprocessing when the results of a time-dependent simulation have been transformed to the frequency domain using a Time to Frequency FFT study.

The feature only operates on the scattered field variables and is thus especially well suited for analyzing the results of a scattering problem. Such a model can be set up by using the Background Acoustic Field feature combined with the Absorbing Layers. Since the time explicit formulation is very memory lean, scattering problems that cannot be solved in the frequency domain can be handled with a time domain approach and an FFT.