In a video, Mark Zuckerberg, boss of Facebook, or: Meta, explains how he imagines the Metaverse: a virtual reality in which we immerse ourselves with a VR headset – made by his company, of course.

Above all, this metaverse looks awesome, high resolution, smooth, colorful. Zuckerberg’s avatar sits in a virtual room with his friends’ avatars at a poker table.

But how realistic is that?

“When I’m in virtuality and I see a table in front of me and I want to touch it, my skin doesn’t feel anything, I don’t feel any resistance”, explains Patrick Baudisch, head of Human-Machine Interaction . department of the Hasso-Plattner Institute in Potsdam.

“Then it’s at odds with the world I’m trying to get into. That’s why scientists are also trying to add this next sense to it. So not just reconstructing sight and hearing in this world , but also Feel.”

Patrick Baudisch is among those looking for “haptic” VR interfaces, that is, the possibilities not only to see and hear virtual environments, but also to experience them with our sense of touch.

Until now, virtual reality that can be experienced physically only existed in the laboratory

Science fiction writers have been fascinated by this idea for decades, as have the current masterminds of the metaverse, of course. However, there is still a long way to go before this idea can come to fruition. In practice, VR worlds that can be experienced physically are only found in the laboratory:

“There’s a whole range of sensations that I can communicate, explains Baudisch. Basically, two categories: one is called touch. These are things that produce the stimulation of the skin. So what I’m trying to do on the surface, for example at the fingertips of the user, it is to have the impression of touching something.”

The other category is that of “proprioceptive” devices, intended to create the sensation of resistance, for example. “Well, if I sit on the chair or lean against the wall, they try to produce resistance for me.”

The vibrating alarm as tactile simulation

We all know the simplest tactile stimulation: cell phone vibration technology. It can also be used for virtual environments:

“There are very simple ways, like having a controller vibrate when you go somewhere or touch something. That’s not very realistic, of course, because a product doesn’t vibrate when you touch it,”
says Philipp Rauschnabel of the Bundeswehr University in Munich.

“When I now touch the cup of coffee in front of me, the cup does not vibrate, but I hold the cup in my hand and I just feel that there is something. A slight difference in temperature, a certain weight. I notice that I can’t press any further and you can’t do that with the controller.”

Simulate “touch” with an exoskeleton

However, the perception of a real “touch” can be simulated using special hardware. This requires a corset that surrounds the whole body or certain extremities.

“An exoskeleton, for example, or a complete suit, in which the body is inside and the individual areas can then also be physically moved. There are skeletons that have a leg in them, for example, and then I can move my leg,” says Rauschnabel.

“This movement is then transmitted one by one, that is to say bilaterally, this means that this exoskeleton can also move from the outside, that is to say that pressure is exerted on the body in VR and that is then transmitted to my actual leg or arm.”

You cannot sit in a virtual chair

It can still work as a simulation of a sensory perception, for example if you have just kicked a virtual ball. But as soon as Mark Zuckerberg actually sat in the virtual chair with his friends, it would become painfully clear: the chair is only virtual. The real Zuckerberg would land on his pants.

Newton’s third law describes this problem: the formation of opposing forces.

“To produce a counterforce, you traditionally need a large mechanical solution,” explains Patrick Baudisch.

In other words, if I want to sit in VR, for example, a real robot arm should position a real board under me in real time. And in such a way that I think it’s the seat of the virtual chair.

“And that’s exactly why these things aren’t really at scale right now. In principle, computing is expected to start from large and complex things to become smaller over time,” says Baudisch. revolves around Moore’s Law. This means we expect it to be half the size and maybe half the price after 18 months. This is traditionally not the case with mechanical solutions.

“We are in an early development phase”

When it comes to consumer products, we’re barely past vibration: the best haptic interfaces you can buy these days are vibrating vests. With them, hardcore gamers can simulate hitting their own body in first-person shooters.

But setting up such devices is only for people with an affinity for technology. Not to mention that VR headsets are always heavy to handle: they’re heavy and mostly awkwardly wired, it gets hot and humid underneath after a while, and drinking real coffee at the same time has its own risks.

Philipp Rauschnabel is therefore skeptical as to whether the tangible metaverse really awaits us at the next bend:
“We are in an early development phase. For private use, there is still a lot of work to do so that these devices are then simply compatible and no long configuration is necessary, no long calibration.