From the wikipedia page on a now prominent 3d virtual idol "From 'Things often confused with holograms' on the Wikipedia page linked above: 'In 2010, there was a series of concerts ... which included Hatsune Miku ... performing on stage as a "holographic" character. This effect was actually achieved through a special method of rear projection against a semi-transparent screen."
How exactly was she created/made since it supposedly is not a hologram?