Tupac: A look behind the hologram

Coachella has been attracting bigger and better music performances, but 2012 saw not only the top hip-hop stars of today but a legendary rapper from the past: Tupac Shakur.

The life-sized figure of Shakur, who died at age 25 in a 1996 shooting, appeared on stage with Snoop Dogg, momentarily stunning the nearly 90,000 fans in attendance.

Getting Tupac's likeness correct was of the utmost importance for Dylan Brown and Philip Atwell, the film and music producers who commissioned the project. They had to make sure Tupac's fans and family would be happy with the end result. The creation was not a simple process. Most digital renderings of humans are done with the real-life subject in the studio to use as a model. With Tupac, animators had only images, video and personal recollections.

SOUNDBITE: Philip Atwell, President, Geronimo Films, saying (English):

"It was like we had good Tupac days and we'd have bad Tupac days. For a long time we didn't show anybody what we were doing because the process was really one of those things that when the last touch was put on, it was like, okay, then we're there."

The image was developed by a company that has made a name for itself in impressive digital effects: Digital Domain. Ed Ulbrich, the Chief Creative officer at Digital Domain, said that despite the company's Academy Award winning work for visual effects, the Tupac project pushed everyone out of their comfort zones.

SOUNDBITE: Ed Ulbrich, Chief Creative Officer, Digital Domain, saying (English):

"But I still don't want to discount how incredibly difficult it is to create a digital human being. That's still the hardest thing that can be done."

What sets Tupac's appearance apart from other resurrected celebrities is that the Coachella performance is an original, foregoing any previously recorded footage of the rap star.

While bringing celebrities back from the dead opens an array of marketing opportunities, the next "live" performance by Elvis, Johnny Cash or Ray Charles will likely face significant hurdles including copyright concerns over their image and music.

Lindsay Claiborn, Reuters.