Computer generated images had been around for a while, but this was probably the biggest crowd of them on the screen at one time.
It is appropriate that this high-tech demonstration, which would have been science fiction a few years earlier, should debut in one of the grandest science fiction tales of all time.
Still, even this tour de force had its limits. The reason it worked so well was that it wasn’t necessary to show much detail. The figures were at a distance, so details were mostly invisible, anyway. Some of them were walking, and others were standing. It was a good demonstration, but it was definitely an early effort.
However, other things will come from this, and this famous scene will be remembered as a landmark of its era. A few subsequent films have used computer generated crowd scenes – the deck shots in “Titanic” are an example – and each gets more realistic. Someday, those Clone Troopers will be numbered among those who started it all.