"To create a completely synthetic human being is the most complicated thing that can be done. This is not found footage. This is not archival footage. This is an illusion."
"This is just the beginning," he said. "Dre has a massive vision for this."
Note that the 2Pac projection is not actually a hologram, according to The Journal, but rather a 2-D rendering, while holograms are 3-D images. At Coachella, 2Pac's computer-generated likeness was projected onto a slab of reflective Mylar plastic, a technique that was also used in Gorillaz' 2006 Grammys performance with Madonna, The Journal notes. The roots of the illusion date back to the 19th century.
From Pitchfork:
And then they answered my question about how they did it... kinda...
The reason he doesn't have tats anymore is that it's not archival footage. they mapped images of him into a 3d model and then they're cutting his voice together and projecting it on a moving screen a little bigger than a man.
So basically, 2Pac2012 is the first official American attempt at an Idoru.