Sony has transformed a swank event space in downtown Seattle into a sea of make believe. Journalists smack ping-pong balls, wield swords and buzz the hair off imaginary scalps. Five years ago, this demo of Sony’s upcoming PlayStation Move motion controller might have elicited giggles and raised eyebrows from the grown men and women men milling through, cocktails in hand, but this is the post-Wii age. No one bats an eye.

And that might be a problem for Sony. The glowing neon balls are new, but we know the concept all too well. Sony’s PlayStation Move looks a lot like an overhyped, late-to-market version of the Wii.

So why isn’t it the Wii, again? Despite the overwhelming similarity, Sony’s Move controller does add a new dimension to the motion control we know and love. Here’s how.

The Magic is in the Ball

Ask any of Sony’s code maestros just how the Move is different from the Wii and they’ll adopt the same look of veiled exhaustion. They’ve heard it more than a few times tonight.

“We have these!” one Sony dev grins after pausing for a moment to decide how to cover it for the hundredth time. He holds up the colored balls on the end of the Move controllers.

He’s not exaggerating. The ping-pong ball look-alikes at the end of the Move controllers are precisely what set Sony’s technology apart from anything Nintendo or even Microsoft will offer. While the accelerometers inside the controller act much as a Wii does, the balls provide what Sony calls a zero point – an absolute location in physical space for the system to peg all the other data to.

A what?

Sony engineer Anton Mikhailov compares the inertial sensors in a Wii remote to walking in a dark room: You know how quickly you’re walking, and can feel yourself turn, but without seeing your surroundings, you have only a vague idea where you actually are, even if you’ve navigated the room a dozen times.

“The problem with inertial sensors is that they tell you where you’re going, but not really where you end up,” Mikhailov explains. Although the Wii’s infrared sensor bar gives the remote some pointing ability, the triangulation used to roughly plot the Wii remote’s location results in some uncertainty. “You don’t know with the Wii sensor bar whether you’re turning – like in the pointer scenario – or moving. Because of that ambiguity, you can’t discern whether you’re moving in space.”

In contrast, the colored ball used on the Move remote tells the PlayStation exactly where you’re standing in front of the TV. Simple left and right movement of the dots can tell the system where you are on an X and Y axis, while the size of the ball tells the system how close or far you are from the TV – that critical Z axis. Attach all the accelerometer and gyroscope data to that point in space, and you have the Move.