Xflow is a completely differnt kettle of fish. It is a souped up version of a lattice-boltzman typoe code. The plot in the video is likely a vorticity plot and it is a volume plot where the transperency is likley proporational to the square of the quantity (square relationship is the defualt in the code) - which is what makes the plot. I agree is looks ery cool. No flow trajectories ae plotted in that view.
The pedigry of Xflow is fromthe movie special effects arena - not the typical place for a scientific flow code to originate from.
Helpful as always.