It is of course almost impossible to tell by watching 2D video of it, but it kinda looked like the they were basically flat animations that were just in a different plane than the other people on the stage. Or were they actual 3d images?
It was the Pepper’s Ghost illusion, projecting onto a sheet of glass. Therefore, in essence, 2D.
Though there may have been 3D involved in the creation of the footage.
Also known as the “Scooby-Doo Gambit” 
Pepper’s Ghost is fully 3D. Video projection onto a screen, however, is 2D. I’m guessing they actually did the latter-- I’ve certainly seen other performance gimmicks labeled as holograms that worked that way.
Should have asked the question sooner. I was at a party over the weekend with a guy who did a fair bit of work on the Michael Jackson one.
But I can’t go back in time and ask him interesting technical questions about it. And I’m unlikely to see him again soon.
The work I’ve seen on it indicates that it was 2D. Nothing that would be necessary to make it 3D seems to be involved. The planes do seem to be slanted in a way to make them not look so flat, they still are flat. They count on the distance from the stage to make this less noticeable.
I see what you’re saying. But the principle remains the same, with reflections onto tilted sheets of glass and not any actual holographic technology.
Link for the pop culture challenged?
The image of Tupac and Jackson is flat as it is a reflection on a flat transparent reflective surface. The 3D effect for the live audience is caused by placing real people and/or objects in front of and behind this surface creating the illusion that the projected image is “among” the real stuff.
The Tupac performance used a tech called Musion Eyeliner which projects the image onto a white floor. Above this floor is a special reflective proprietary foil screen. The bottom length of this screen is at the foot of the stage and it extends out and up at a 45 degree angle towards the audience. It reflects the image on the floor below it but is clear so people and things can be seen on the stage through it. To the audience it appears that the projected/reflected image and the live people are on the stage together. I saw it at the Universal Studios attraction “Disaster!” which uses it to make it appear as if Christopher Walken is there. I understand it is also used in the Harry Potter attraction.
The company that did Michael Jackson uses a similar arrangement but the the image is projected, again from above, but onto a rear projection screen suspended above and parallel to the stage floor. The transparent screen is again a 45 degree angle to the audience reflecting the image that is above.
Seconded - what are we talking about?
This happened a couple of weeks ago. And a couple of years ago a similar appearance by the long-deceased Tupac.
OK, that was singularly unimpressive. Basically all it was was a movie of Michael Jackson with some dudes wearing miners’ lights dancing in front of it. It didn’t look like they even had any live people behind him.
And if randwill’s description is accurate, it’s a sort of combination of Pepper’s Ghost and flat projection. It’s flat not because the (half-) mirror is flat, but because the floor it’s reflecting is flat. Put a real (or impersonator or animatronic) Michael Jackson underneath the floor, and you would get a 3-D image of him/it.
Billboard Music awards? That’s the only reference I can find to it.
These presentations will never look impressive on television because you lose the third dimension. On TV, yes, it just looks like a video of Michael Jackson.
However, it should be noted that the movie of Michael Jackson in this case was created without Michael Jackson. It is a wholly computer generated figure. Here’s an article that talks about the projection process as well has the difficult task of making a life-like M.J. from scratch:
Make sure to check out the schematic views at the bottom of the page which explains how it all works better than I could describe it above.
It never had the third dimension to begin with.
OK, that’s impressive.
The presentation has actual physical depth in that there are people and set pieces in front of and behind the screen onto which the character’s image is being projected. To people in the audience with depth perception this creates an illusion of 3D. The projected character doesn’t have depth and never will as long as it is projected on a flat surface.
I wondered about that when they did the Tupac one, although I certainly wasn’t going to watch an awards show to find out! Wasn’t there a similar one of somebody else around the same time?
How can these things be called “holograms” by any definition of the word?
The makers of the Michael Jackson presentation reject the use of the word ‘hologram’ in the “USA Today” article I posted a link to above. The current issue of “Entertainment Weekly” has a feature titled, “Big Moments in Hologram History”. It starts with Dennis Gabor inventing the concept of holography in 1947 and includes Holo-Leia in the first “Star Wars” movie, the holodeck from “Star Trek:TNG” and Tupac Shakur at Coachella among several others. None of the things they list are actual holograms. Until we have actual holograms I’m sure the word will be used to indicate hologramish things.
None of the audience was close enough for stereoscopic 3D, and it looked like all of the people “behind” Jackson were just part of the same movie. To make best use of the effect, they really should have had some of the dudes with mining lamps (who were seen before the curtain opened) walk around behind the screen.
And again, the surface being flat is irrelevant. Mirrors are flat, but that doesn’t stop them from producing 3D images.
Gorillaz had a “live” performance at a concert or awards show several years ago that was basically the same Pepper’s-Ghostish technology, I think.