The Volume FFT SOP computes the forward or inverse Fast Fourier Transform of input volumes. The volumes should be specified in pairs, representing the real and imaginary parts of complex number input and output.
For best performance, volume resolutions should be a power of two.
To take the forward FFT of a typical real-valued volume, an empty volume of the same resolution should be provided as the zero-valued imaginary input, and to hold the imaginary spectral output.
name attribute is an effective way of specifying pairs of volumes
in the Source Group parameter, e.g.
@name=X_real @name=X_imag @name=Y_real @name=Y_imag.
Enabling Center DC to shift the DC component to the center allows easier visualization of spectra with the Volume Slice node.
The volume primitives to be transformed by FFT.
When performing a forward FFT, shift the DC (zero-frequency) component of the spectrum to the center of the volume. When performing an inverse FFT, assume the DC component is located at the center of the volume.
Calculate an inverse FFT.
Apply a normalization factor so that a forward FFT followed by an inverse FFT yields the original input.
Compute 2D Slices
Treat a 3D volume as a series of 2D transforms along the specified axis.