If you enter a virtual environment that does not use motion tracking technology, it will not be very rewarding to visit. Motion tracking is the digitization of motion to be used by computers. This technology is critical to creating a high-quality VR experience like 3D configurators.
Without motion tracking in VR, you would feel somewhat restricted in the virtual world and not be able to look around, move and explore. The best scenario would be to use a gamepad to control movement within the virtual environment, but that would only serve to destroy the feeling of immersion.
The ability to intervene and interact with the virtual world the moment you pull your VR headset is critical to creating an immersive experience.
In the real world we use our hands, we turn our bodies, we move our heads and the virtual world has to imitate this movement. Of course, there will be times when a VR experience requires sedentary integration, i.e. a flight simulator where you sit in a cockpit with a joystick.
But there will be nuances that determine or break their state of immersion. The possibility to turn around naturally and look out of the window or look at the virtual dashboard keeps the illusion going.
For this purpose there are already a number of different methods and technologies available to make the most of exploring a virtual environment. But how do they work? And where should you start by choosing the right one for your particular VR experience?
In the following article, we have provided you with a brief overview of the basics of this technology and the options currently available. But first…
What is tracked by Motion Tracking?
First of all, it is important to understand how an object can move in three-dimensional space. This can best be explained by the concept of six degrees of freedom, which refers to the freedom of movement of a rigid body in 3D space.
Essentially, the body can move forwards or backwards, upwards or downwards and from left to right. In other words, in three vertical axes. This is then combined with a rotation around these axes, often referred to as pitch, yaw and roll.
So any motion tracking system worth its money must be able to measure motion across all these different degrees.
Motion Tracking Technologies.
There are some options to support motion tracking and these are generally categorized as optical and non-optical tracking.
Optical tracking uses image sensors to track the movement of the body. Meanwhile, non-optical tracking uses a number of sensors that can be installed in hardware or attached to the body, but the more advanced options can also use sound waves or magnetic fields.
Most modern tracking systems combine optical and non-optical methods to increase accuracy, and as these sensors continue to improve, it has led to the development of smaller and more accurate systems.
Optical Motion Tracking for VR.
The optical methods used for motion tracking typically use cameras to track the movement of an individual. The person being tracked must carry optical markers that are placed at specific points on the body. In addition, they can be placed on hand controls or a Head Mounted Display (HMD).
You may be familiar with this concept of motion tracking if you`ve seen a film like “The Lord of Rings: The two Towers” or “The Rise of the Planet of the Apes” in which actor Andy Serkis wears a suit with highly reflective markers so the cameras can track his movements in real time.
However, the commercial systems used for VR motion tracking use only a few strategically placed markers.
How does it work?
When everything is set to track motion, the cameras that can calculate depth register the marker and assign it to the 3D environment.
These reflective markers are also called “passive markers” because of their tendency to reflect light. And this means that there is a corresponding form of tracking that uses “active markers”. These are computer-controlled LEDs that give the user much greater accuracy in tracking motion.
Due to the fact that these LEDs need to be powered, active markers for consumer VR devices are not widely used. Most HMDs on the market that use markers for motion tracking have passive markers.
And yet one of the most notable exceptions is the Sony PlayStation Move Motion Controller. It uses a large light that the console follows over a camera. Although it`s not quite as advanced, the active markers of the movie studios that Gollum and Caesar gave us, the PlayStation controllers continue to be supported by non-optical sensors to improve their accuracy.
Other notable examples.
The most popular and probably the most successful consumer motion capture device is undoubtedly Microsoft`s Kinect. When used with the Xbox and Windows computers, Kinect is able to track incredibly motion without using active or passive markers.
His camera just needs to be able to see the person standing in front of it. And the latest version can track up to six people at the same time. However, despite the use of some very innovative software and boundary depth and infrared cameras, it is not yet able to map the exact nature of the marker-based tracking platforms.
Another example of a tracking system that is not based on markers is Leap Motion. When connected to an HMD, this device can track the user`s hand movement, providing a natural way to interact within a virtual environment.
The next step to optical tracking.
The next logical step for commercial VR systems will be tracking the entire body. However, systems that complete with the professional (and expensive) systems are probably still a long way off today.
Most VR hardware is designed to be used safely while sitting. Walking around unsupervised while wearing a VR-HMD can cause injury.
However, the talented SteamVR team has developed something that could change this scenario. It is called the Lighthouse Tracking System and is a laser-based tracking device that can locate passive markers attached to SteamVR controllers and HMDs. It then maps the objects in the room and provides some important security measures to prevent you from hurting yourself when moving in the virtual environment.
Non optical Motion Tracking for VR.
You may not be aware of this, but the VR devices currently available probably all contain small electromechanical sensors. These are typically gyroscopes, magnetometers and accelerometers that fall under the category of non-optical tracking.
Microscopically small, these sensors are used to measure and track certain movements. For example, the accelerometer measures motion along the three-dimensional XYZ axis while the gyroscope measures 360-degree rotation. And the magnetometer can measure the direction of a magnetic field, i. e. it can determine, for example, in which direction the magnetic north runs.
These sensors are now incredibly affordable, small and accurate, thanks to technological advances in the automotive, aerospace and computer hardware industries. They are now a major pillar in all modern smartphone and tablet devices and VR headsets have followed suit.
How does it work?
In combination, these three small sensors deliver incredibly accurate motion data with very low latency. Complemented by optical tracking methods, including active or passive markers or infrared cameras, these non-optical tracking devices provide a robust and rounded motion tracking solution.
But when it comes to a self-contained system, these sensors are more than capable of holding their own. Just look at the sheer number of VR smartphone apps and headsets available today to prove this claim.
Other notable examples.
The alternative non-optical methods in practice are strongly reminiscent of science fiction – but they are scientifically well-founded.
Take, for example, the direct electromechanical tracking of body movement. In a VR context, this could be achieved by a haptic glove that transforms the movement of the fingers into signals for tracking.
Another method is the use of an exoskeleton, which can provide haptic feedback as well as motion detection. Well, These are far from commercially available, but the progress companies like Dexmo are making is encouraging.
Finally, the Virtuix Omni treadmill is another example of a mechanical motion tracker. Not only does it allow the user to run in all directions within the virtual environment, but it also tracks and measures motion, albeit somewhat roughly compared to the other methods already mentioned.
What will the future bring?
It is clear that there are a number of existing and potential technologies that will have a far-reaching impact on the VR industry.
And it is certain that both non-optical and optical tracking methods will be used in these motion tracking platforms for some time to come. But the ultimate goal of VR technology is certainly to transport and immerse the user in a completely virtual environment where he does not have to move his limbs and head at all to explore the virtual environment.
As sensors continue to improve and electronics become smaller and smaller – not to mention work in the field of nanotechnology – the idea that one could soon experience a matrix-like immersion is not too far-fetched.
But for now, if you want to make the most of today`s VR systems, you have to use motion capture technology.
How can Appeal VR help?
With the advances in motion tracking and the non-optical tracking systems present in modern smartphones, there`s a chance that by developing a state-of-the-art-VR application, you can really make a difference in your industry.
Thanks to our unmatched experience in developing custom VR apps across multiple industries, we can guide your innovative app concept through the key design and development phases. We then create an effective application that will change your business and make your industry sit up and take notice.
So, are you ready to take the first step towards realizing your VR app idea? Then contact us.
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