It's not pedantic because it has a material effect on what we're lead to believe this is. This is hacker news. A hacker knows (and cares about) the difference between a "3D hologram" and Pepper's Ghost illusion, and that distinction is important in understanding what has been achieved.

This is definitely a cool hack, but it does not involve 3-dimensional projection. This is a 2D image cast on to a 2D projection plane with no stereoscopic effect. That makes the term "3D hologram" a misnomer at best, and a gross misrepresentation at worst.

Because of this mislabeling, we're all sitting around talking about the inaccuracy of the title, rather than the fun part. That's the fault of the person who titled the article, not the person pointing it out.

Too late to edit my top comment, so I shall reply here: I apologize for perpetuating the problem, because now there's several top comments discussing how parent was actually correct, and the real discussion is yet again derailed.

The first thing he said is that it's cool. And he's right, it's not a hologram; some of us care about that, and would really like to see actual holograms. It's not an attempt to take away from the achievement here, rather a desire not to exaggerate it.

Down-voted your comment because you are confusing the truth with being pedantic.

This demo is neat. No question about it. I like when people play with ideas like this.

The demo isn't any more a hologram or 3D than if I took four LCD's, arranged them as the sides of a cube and turned down the lights. Other than not seeing through the LCD's, the images would be the same.

Again, as the person you are accusing of being pedantic said, this is no hologram and it isn't 3D in almost any imaginable way.

Notice how he moves from angle to angle quickly with the camera? That's because there are no volumetrics here. It's just a flat 2D image effectively seen through a 45 degree partial mirror.

It's a 2D image that appears to float in space. And it's cool.

Many, many years ago I thought about the idea of installing a screen spinning or translating (harder mechanically, easier imaging) at high speed in a vacuum chamber with transparent walls and then using lasers to project slices of a true 3D scene onto it. Challenging, but it would be really interesting to see how something like that works out.

It's not even "perceptually 3D" though. It's a 3D rendering projected in 2D.

How did you get a leap motion? What do you think of it?

I'm not ajacksified, but I have a Leap, which I got by joining the developer program. I love it.

I've been writing about it at http://leaphacking.com

Leap has announced that the devices will be available to the public on May 13.

I've been hacking around using JRuby and JavaScript. It's quite nice to work with, and so far my biggest issues are thinking through just how to handle user movement (i.e. what hand/finger combinations and movement should equate to what action).

It's a nice compliment to the XBox Kinect, too.

Gesture recognition has been added so I need to spend a bit of time with that today.

I was lucky enough to give a presentation at an Intel "Perceptual Computing" meetup (their version of the LeapMotion), and I met a dev advocate from LeapMotion.

I think it's very interesting; the API is solid, and it's really easy to use with Javascript because you can interface with it directly through a Websocket server. That, plus three.js, means you can do some interesting things with examining 3D models. It isn't a far stretch to see medical and industrial applications, as well as interesting games (Infinity Blade, laptop edition?)

There are a few companies working on this at once[1]; I think it's definitely something to keep an eye on. It seems like a natural evolution of webcams.

[1]http://news.ycombinator.com/item?id=5339266

Honestly, part of why I come here is for instant debunking of hype. So I appreciated it.