3D DUS files are very similar to the revolution-defined DUS files. However, in this case, the sound pressure wave depends on both theta and phi coordinates and therefore:
- There is only one type of 3D DUS files, unlike in REV files.
- It is necessary to specify both theta and phi values for each sample of the sound pressure emitted field.
In consequence, the 3D DUS file format is defined as follows (each list item corresponds to one line in the file):
- A header line usually reserved for information on the program that generated the DUS file and information about the file.
- The type of DUS file. In this case, it is the string "3DE" (without quotes).
- The component of the field that is defined in this file. It always is "Ptotal" (without quotes).
- A comment line, ignored by the software, that can hold any content.
Several values separated by whitespaces. These values are, in order:
- Initial theta value.
- The number of theta samples.
- The theta increment (the difference between two consecutive theta samples).
- Initial phi value.
- The number of phi samples.
- The phi increment (the difference between two consecutive phi samples).
- Another comment line that can hold any content.
- For each combination of theta and phi samples, four values, separated by whitespace, are provided: the theta value, the phi value, the amplitude of the emitted sound pressure wave (in dBPa) and the phase of the sound pressure wave (in degrees).