The Exterior Field Calculation node is the feature that sets up the Kirchhoff-Helmholtz integral to perform the postprocessing of the scattered field. It is per default added to all the scattering boundaries. The selection is not locked so it can be modified but it should in general coincide with all the Wall boundaries of the Scattering Object. Only one Exterior Field Calculation feature can be added to the interface.

Enter a name for the Exterior field variable name and select the Type of integral. See the Exterior Field Calculation node in The Pressure Acoustics, Frequency Domain Interface. Note that no symmetry options exist for this interface.