Virtual Reality Tracking
Now that the big 3 VR HMDs are out it is time to talk about tracking. Some things work and some don’t. When you watch videos of any of the helmets it is easy to think they all work flawlessly, which obviously isn’t true.
When you have time to play with all the options you will find that they have their pros and cons. I am going to dig into the pros and cons of the PlayStation VR, Oculus Rift, and the HTC Vive. This is not meant to bash any particular option, merely set expectations for each of your options and to talk about what works and what doesn’t.
The obvious start is the Oculus Rift. It was the first ultra popular consumer option and it is for a good reason. The original Oculus (DK1) didn’t use any sort of positional tracking, just a gyroscope. With the second iteration the infrared system was introduced. The HMD emits IR LEDs which are tracked by a camera. With the DK2 it was a single camera which you would mount on your monitor.
For Oculus CV1 (consumer version) you are using the same system. The HMD emits infrared LEDs which are tracked by a sensor you place on your desk. You can use multiple sensors but I will get to that in a minute.
This system works fine, so long as you are facing the sensor. For games that use the game pad or the remote you will not have too much of a problem, when you spin around it works fine, you can look wherever. The issue is when you start using touch.
I am a huge fan of the touch controllers, they fit nice in my hands, I have large hands so I was surprised. In my previous article I talked more about input methods so I wont talk too much about why they kick ass but I will say they come with a second sensor. This helps but for some stupid reason you can’t position the sensors far enough apart to be useful.
Recently I was able to test using 3 sensors with my rift. I connected my Oculus, touch, and 3 sensors to a computer. I tried setting up the sensors in a way that surrounded me and would track from all angles. When I sent into the setup wizard I was told they were too far apart. Even adding additional sensors requires they are not more than 3 feet apart and facing directly at you. This is fine for stationary stuff that doesn’t ask you to turn around but if you try to play a room scale game on SteamVR you will run into issues almost immediately with your hands flying away.
At the end of the day the sensors work fine for the recommended play area and types of games Oculus wants to push. I am just a little too used to room scale now.
The Vive is HTC’s SteamVR option. It is full room scale and accomplishes this by using their lighthouse solution which is nicely open source. You mount a maximum of 2 lighthouses to the wall, which works for multiple players in the tracked area. You can walk around the space and interact with your game.
The sensors do not connect to your computer, they sync with each other and emit a class 1 laser field horizontally and vertically which are read by the HMD and controllers to understand where they are in the space. SteamVR will barf at you if it detects more than 2 sensors in the visible area.
This solution works super good and is accurate, since you place the light houses on opposite ends of the play area you are tracked no matter which way you are facing. You will run into issues with multiple people in the same space because you can obstruct the view of the other players.
The huge down side of this solution is you need way too much space to have fun. I find it super anticlimactic to use a vive in a standing room only play area, since room scale is pushed so hard. I find it difficult to set this up at my house because my normal play area in the basement is not that large, I can set it up but it is not always super comfortable. In the lab it works fine because we have loads of space.
Bonus: I have found using an XBOX Kinect in the play area of the Vive interferes very minimally.
The PSVR uses something different. The tracking system for the PSVR is actually the same one they developed for the PlayStation Move controllers. A camera mounted on your TV tracks the move controllers and the HMD. It does the job but it falls into the same way issues as the Oculus DK2, where you are only tracking from the front.
Titles like Job Simulator which are developed for the Vive and ported across the board are the most apparent. The PlayStation VR expects that all the action is going to happen in front of you (which is true) and you will need to turn around as little as possible. But even in the exclude Batman title when I turned around my body was blocking my hands which prevented me from tracking properly. I also find that when you are standing still the tracking can drift a little.
You can combat issues with tracking by avoiding natural light in the background. I made the mistake of setting up my PSVR in my living room with a large window behind me which was fine in the evening but during the day did affect it, this will affect any tracking system, I recommend a basement or dark room for best tracking.
Hololense (Microsoft AR/VR)
The Hololense, and the upcoming Windows VR HMDs are unique because they offer an inside out tracking system which is the complete opposite of the other HMDs because instead of an external sensor tracking or emitting a field, the HMD itself is tracking the world around it. This is similar to the Project Tango tablets which I intentially left out because it is a tablet (it does work for VR).
The Hololense uses similar technology to the Kinect in that it has multiple sensors tracking depth, colour, and tracking your hands so you can interact with digital objects. The new HMDs will work in a similar way. There is a downside though, this does not work at all outside or close to large windows because of the lasers in the headset that are tracking.
Every set on the market right now works. I am strongly in the Vive’s court right now for tracking an entire room and many objects in it. The space is a huge down side but it isn’t that bad. The Oculus is good for sitting and gaming and the PSVR is going to be the best option for less technical people who already own a PS4.
The Lighthouse tracking system being open source is hugely important because it is going to become a standard tracking system for many VR and AR applications.