Understanding Virtual Reality – Technical Specifications and Basic Concepts

Most of us have heard about virtual reality, but many only have a general understanding without knowing the components that make up virtual reality and the concepts related to VR specifications.

In this article, we will explain the fundamental concepts of virtual reality (VR). The specifications and commonly encountered technologies are essential for making informed decisions and choosing a VR headset that suits your needs.

The author will present the information in the simplest way possible, minimizing the use of technical jargon and adopting the perspective of someone new to VR to make it easily understandable.

What is Virtual Reality? VR Definition

Virtual reality, abbreviated as VR, allows people to immerse themselves in a pre-designed simulated space created by programmers. Virtual reality headsets consist of basic components such as a screen (or two separate screens) placed on a frame worn on your head, along with accompanying sensors depending on the features of each headset (sensors may be integrated into devices attached to or on the headset). The content is coordinated through standalone hardware or hardware integrated directly into the headset.

We will have a more detailed article explaining virtual reality and its operating principles. In this article, we will focus on the main part, which is explaining the technologies, concepts, and technical specifications commonly integrated into VR headsets.

Common Concepts for Virtual Reality Headsets

What is FOV (Field of View)?

Field of View, abbreviated as FOV, refers to the extent of vision or viewing angle. In general, a higher FOV means a wider field of view. FOV is measured in degrees.

FOV is a commonly referenced specification in VR headsets, describing everything you can see within the virtual reality headset. According to some sources, the FOV of an average person is approximately 180 degrees.

Most VR headsets today have an average FOV of about 110 degrees. Exceptional cases include the Valve Index VR headset with a FOV of 130 degrees or Pimax VR headsets, offering a maximum FOV of up to 200 degrees, providing a broader VR field of view.

Due to the average FOV being around 110 degrees, you might notice a black border around the headset when you look through it. However, with the current design of VR headsets, this border appears more like wearing safety goggles, allowing you to easily overlook its existence and focus more on the VR content.

Degrees of Freedom (3DOF, 6DOF)

This specification is quite crucial, determining the ability to move and use a VR headset.

All phone-dependent VR headsets support 3DOF, while most PCVR headsets support 6DOF.

What is 3DOF?

3DOF tracks the roll, pitch, and yaw axes. In simpler terms, 3DOF only tracks the head based on the movement of your neck.

For 3DOF VR headsets, you only need to sit down, and you can use them with just the movement of your neck. Your physical movement won’t have an effect. This limitation is most common in phone-dependent VR headsets.

The Oculus Go standalone VR headset is a notable example of a high-quality VR headset using 3DOF technology.

What is 6DOF?

Similar to 3DOF but more advanced, 6DOF allows tracking not only the head’s movement but also the physical movement in your space.

This means that high-end VR headsets supporting 6DOF allow you to move within your physical space, stand up, sit down, and use your neck to turn horizontally and vertically comfortably.

Most high-end VR headsets nowadays support 6DOF.

Types of Motion Tracking (Inside-out Tracking, Outside-in Tracking)

From this section onward, we will only discuss VR headsets that support 6DOF. VR headsets that only support 3DOF in the lower segment will be discussed in another article.

All high-end VR headsets require tracking through some technology to monitor your space and movement. There are two current tracking technologies: Inside-out tracking and Outside-in tracking.

What is Inside-out Tracking?

Most VR headsets today use Inside-out tracking. This means that cameras are integrated into the headset to look out into the surrounding space, creating a map and additionally tracking the motion of controllers, etc.

VR headsets like Oculus Quest, Oculus Rift S, Vive Cosmos, or Windows Mixed Reality headsets are all integrated with 2 to 6 cameras on the headset to serve tracking and analyze these images.

Using Inside-out Tracking technology simplifies the setup of VR headsets and makes them more compact.

What is Outside-in Tracking?

Outside-in tracking means using an external sensor or base station to track your movement and transmit it to a processor (usually a computer). The processed images are then displayed appropriately on your VR headset.

Outside-in tracking is an older technology; even the first-generation VR headsets on the market, such as Oculus Rift or HTC Vive, used this tracking technology. However, using external sensors is still the gold standard in tracking technology. Specifically, current top-of-the-line VR headsets like Valve Index, Vive Cosmos Elite, and Pimax use external sensors for tracking.

Using external sensors provides nearly perfect tracking accuracy, suitable for professional gamers or simulations that demand high precision.

Controllers

Currently, there are well-known VR headset manufacturers such as Oculus, HTC Vive, Sony, Pimax, and Windows Mixed Reality manufacturers like Samsung, HP, Acer, etc.

In essence, the function of controllers from all manufacturers is similar. They all track hand movement, hand status, and hand position.

However, each manufacturer has its strengths. For example:

• Valve Index Controller (Valve Knuckles) can track each of your finger movements. It has force-sensing capabilities that simulate your hands in great detail.
• Oculus Quest has developed a new technology called hand tracking. With this technology, you can completely eliminate controllers and only use your hands for control.

With 4 integrated cameras, the Quest will track hand gestures and perform corresponding actions within the headset. However, this is still an experimental feature, not very smooth. We are looking forward to future updates from Oculus for hand tracking.

Classification of VR Headsets

Aside from VR headsets designed for phone use, there are currently three main types of VR headsets in the market: Standalone VR, PCVR, and Console VR.

Standalone VR

Compact VR trend, Standalone VR headsets are integrated with processors and operating systems. They do not require any other peripherals to use.

Currently, the most popular standalone VR headset on the market is the Oculus Quest. Additionally, HTC also has a standalone version called HTC Vive Focus Plus.

With Standalone VR, you can comfortably take the headset anywhere and use it immediately, such as camping or outdoor activities.

VR Headsets for PCVR

We don’t need to say much about this category. The top-ranking VR headsets today belong to the PCVR category, such as Valve Index, Pimax, Oculus Rift S, HP Reverb G2, Vive Cosmos, and Vive Pro.

PCVR headsets require a high-configuration computer to use, usually requiring a minimum graphics card of GTX 1060 or higher.

The advantage of PCVR headsets is utilizing the almost super-powerful configuration of the computer, providing high-fidelity images, good tracking control, and especially being able to play more hardcore games (heavy games).

The most recent game, Half-Life: Alyx, is also one of the games that made a significant impact, making more people aware of VR. This game can only be played on PCVR headsets.

A weakness of PCVR is, besides requiring a high-configuration computer, the user experience is somewhat less enjoyable due to being restricted by connecting cables. However, HTC has a solution with a wireless adapter that provides wireless connectivity for their VR devices. However, the price is not exactly cheap.

Console VR

Console VR is VR headsets used with game consoles such as PS4 or Nintendo Switch.

Playstation VR (PSVR) is a VR headset used with the Playstation 4 game console.

Nintendo Labo VR for Nintendo Switch is a cardboard-based VR headset that can be assembled like Google Cardboard in the past.

The author himself doesn’t highly rate this category. If you already have a PS4 and want to experience VR, you can get a PSVR. However, if you want to invest in the VR experience from the beginning, it’s worth considering Standalone VR like Oculus Quest or getting a PCVR headset for a more in-depth experience.