Difference between VR Headsets

3DoF vs 6DoF in VR:

In VR, DoF is a common term that stands for Degree of Freedom. The number before it stands for how many different axes are being tracked. It is significant when deciding which type of VR headset to buy depending on it’s DoF tracking.

For instance, when purchasing a VR headset for the purpose of watching 360 videos, then a 3DoF VR headset is enough. This is because you cannot change the distance to the objects in the room. In 3DoF headsets, you can only move in 3D environments with joysticks but not your physical motion.

On the contrary, a 6DoF headset is necessary if you want to use it in 3D environments. With 6DoF, your physical movement is also tracked by the gyroscope to allow virtual movement.

There are three main axes which are known as the translational and three secondary axes which are known as rotational.

When a VR device has 3DoF it will either be rotational or translational. But, not both. On the other hand, a 6Dof experience allows for both. Therefore, if you want to track both the head and physical body movements, a 6DoF is definitely the best option for you to buy.

There are 3 categories of VR headsets:

• Tethered VR headsets
• Standalone VR headsets
• Mobile VR headsets

Tethered VR headsets

These VR headsets are physically connected to computers by HDMI or USB cables. They are more immersive than other headsets and a require powerful PC or gaming console:

• 1- Oculus Rift: is a set a virtual reality goggles that works through the connection to your gaming desktop or laptop by DVI or USB port and provides 3D imaginary experience on its stereo screens. The user can see a virtual world with the help of in-built pair of screens that shows two a little bit different images for each eye. There is also a set of lenses on the top of the panels which focuses and reshares image creating a stereoscopic effect. Oculus Rift has sensors that monitor users’ movements and adjust imaginary respectively, providing a feeling that the user is looking around the virtual world.
• Motion tracking: Oculus sensor is able to recognize the motion if you turn your body more than 180 degrees.
• Controllers: Three buttons on each controller with X, Y and Menu buttons on the left. A, B and the universal Oculus menu button on the right. Other buttons also include a clickable thumb stick, a trigger and a touch-pad button (for fingers other than a forefinger).
• Camera: Oculus headset setup has a tracking camera which works with an infrared light. This allows 360-degree positional head tracking in a pretty broad play area, though in short scenarios.
• Oculus SDK: is the best VR SDK for Rift. It includes various engine-specific kits (for Unity, Unreal, WebVR, etc.), samples, asset and audio packages to help build VR apps. There are Oculus PC SDK, for Windows, and Oculus Mobile SDK. This VR dev kit offers lots of features and handles many issues of VR content, like the optical distortion and rendering techniques, for example.
• 2- HTC Vive: is the most advanced VR headset which provides incredible VR experiences. It shows its best quality while using it in Lighthouse room tracking that gives the opportunity to move across the whole room. It has also a dual cameras in the front that help to track user’s hand movements and a 90Hz refresh rate with 70 sensors. HTC Vive also included innovative accessories such as Vive Trackers which are highly adaptable and easy to use. They enable user to bring any object into virtual reality world.
• Motion tracking: It comes with two wireless infrared Lighthouse cameras. Cameras are to be placed in the corners of a room, tracking the headset’s 37 sensors (70 in total, including each controller).
• Controllers: They’re basically a vertically bisected version of the Steam Controller, with a trackpad, buttons and a pressure-sensitive grip in each hand.
• Camera: Front-facing camera, which means users may overlay virtual objects onto the real world surroundings.
• VR SDK: For developers looking which SDK to use to build VR apps for HTC Vive, there are 3 major options. OpenVR kit, SteamVR kit and VRTK — all official virtual reality SDKs by Viveport community. And by the way, Viveport SDK is definitely a starting point if you want to create and share apps for HTC Vive. Now let’s give a brief review of software development kits:
• 1- OpenVR SDK by Valve is an API and a runtime environment with great samples. It supports multiple VR hardware and applications don’t have to be vendor specific. The runtime is of SteamVR.
• 2- SteamVR SDK lets developers create single interfaces that will work on different VR headsets, including HTC Vive. Moreover, it gives access to controllers, chaperoning, models and it also allows content preview in Unity play mode.
• 3- VRTK or Virtual Reality Tool Kit, appears to be a collection of handy scripts for VR applications. It works in Unity3d engine.

Standalone VR headsets

provide users with a more powerful VR experience than smartphone VR but less powerful than tethered VR. These headsets don’t need a PC or a smartphone to deliver a VR experience. They are equipped with built-in processors, memory, battery, GPU, sensors, displays, and more. These VR headsets are uncabled, so users don’t have to limit themselves to a restricted space.

• 1- Oculus Go provides users with the obtainable VR of very good quality at its price-point. It has the 5.5-inch display with 2560 x 1440 resolution. The imagery is crisp and clear with the bright colors. Oculus Go also provides spatial sound which means full surround sound experience that doesn’t require to wear any headphones or anything like that.
• 2- Lenovo Mirage Solo is a standalone headset which uses a technology called WorldSense that enables to be fully wireless and smartphone-free. Lenovo Mirage Solo has a screen with a 2560 x 1440 resolution and 110 degree field of view, so despite being untethered it delivers a memorable experience. It offers 6DoF tracking which means that the user can move around the room instead of having to be seated.

Mobile VR headsets

offer a quite simple and minimal-risk introduction into a virtual reality world. These devices are compatible with most Android smartphones and iPhones, the only requirement — they should fit inside the VR headset. Here are few of them:

• 1- Samsung Gear VR is one of the most widely known mobile VR HMDs available. It is considered as one of the best from available in this VR category because of its connectivity options which are better than the other mobile VR headsets. The Samsung Gear VR only works with Samsung phones which includes the Galaxy S9, S9+, Note 9, Note8, S8, S8+, S7 and S7 Edge. The headset works by using a smartphone as its brains because it deals with all the processing.
• Motion tracking and camera: Gear VR unit acts as the controller, which contains the field of view, as well as a custom inertial measurement unit. This IMU for rotational tracking connects to a smartphone via micro-USB. Gear VR set also has a touch-pad, a back button, a proximity sensor to detect if the headset is on.
• Controllers: The device is only 48.1 x 38.2 x 108.1 mm, and accessing the volume controls, Back button, home screen or touch pad.
• Oculus SDK: The VR headset by Samsung was initially built in collaboration with Oculus, thus their kit fits nicely to build apps for GearVR. Oculus Mobile SDK contains tools and libraries for C/C++ development for Oculus, as well as for Samsung Gear VR.
• 2- Google Cardboard offers a decent introduction for those who have a very tight budget. It isn’t the most comfortable or immersive in the category but it’s a nice choice for those who want to try out VR without a huge investment. This headset works by allocating the smartphone at the optimal distance away from the lenses. After that, by using suitable apps, the lenses create a 3D effect. The user can even move his head and the imagery will change respectively as if he is in the same place as it is shown on the display.
• Google Cardboard is a folding cardboard container, which users can place a smartphone into. It’s universal and supporting a wide range of smartphone models. Google Cardboard viewer includes:
• Google VR SDK: This SDK for Androids also supports Cardboard along with Daydream View. Generally, virtual reality SDKs by Google offer any tools to make VR apps for their platforms, e.g. libraries, APIs, samples and design guidelines. The hardware requirements for Cardboard apps are affordable pretty much to everyone — a viewer and a smartphone.