Full Body Tracking
What is full body tracking?
Full body tracking (also known as FBT) refers to allowing tracking of more than the hands and head in VR, typically referring to the legs and hips of a user. This is typically done using trackers that are worn by the user.
What is full body tracking used for?
Full body tracking, when referred to tracking of the lower body, allows for full pose estimation which is very fun for social VR settings.
You will see this tech used by people who dance in VR or do other active activities, but also by people who spend most of their time sitting, as it just improves immersion for oneself as well.
Keep in mind a majority of VR applications do not make use of FBT, so be sure to check if the software you are using supports FBT before spending money on additional hardware!
So lets say you are interested in acquiring FBT. For the sake of discussion, lets divide types of FBT into 3 general categories:
- Wearable Trackers
- Fake / emulated FBT
- External cameras that track your body
Wearable Trackers
These are trackers that you strap on to yourself. Usually this consists of needing to wear trackers on your feet and hips, though some solutions require more. This solution generally costs the most money (depending on the implementation you choose) but will give the best results, and thus is the most common form.
A lot of these trackers will need some form of straps to have them actually be worn. You can find FBT straps with google searches on store-fronts like amazon, but I personally really enjoy the ones made by EOZ.
Individual trackers are generally separated in groups based on their tracking methodology. It may be worth a read here if you want to know the details.
SteamVR based tracking
Remember, for these trackers you need to have base stations! In addition, each tracker needs its own Watchmen USB dongle to connect, read more here under the dongles section.
For SteamVR based FBT tracking, for tracking your lower body (legs and hips), you will need 3 trackers + straps in most implementations, such as with VRChat. You can mix and match between SteamVR trackers freely,
Vive Tracker 2.0
These can be identified as being larger with a flatter bottom, and have a blue triangle. (Beware the trackers with the same shape that have a grey triangle, those are Vive 1.0 trackers and only work on 1.0 base stations while the blue Vive 2.0 trackers can use 1.0 or 2.0 base stations).
These trackers are among the heaviest of the wearable trackers, yet also tend to have the worst battery lives, often only lasting 2-4 hours. You can get straps with battery extenders for these but that just makes things heavier. In addition, their firmware is a bit funky which sometimes makes them annoying to power on and connect. That being said, they still track very well and are functional, so if you can grab these used for a good deal they may be worth it to those on a budget (you can often find these used for around 50 dollars or so, just be wary about getting watchmen dongles too!)
Vive Tracker 3.0
These can be identified compared to 2.0 trackers as being smaller, lighter, and looking very triangular head on, and have a dark gray logo. Like the 2.0 trackers they work on either 1.0 or 2.0 base stations. However, their inner workings have improved such that they have a significantly higher battery life of over 7 hours, and are much lighter as well. Furthermore, their firmware doesn't have as many quirks about turning on and off like the 2.0 trackers, and they still track great. Of the SteamVR tracked trackers, these generally track the very best are the preferred trackers by many people, and is the best tracker to use for continuous calibration. These can be purchased new for 130 dollars but can often be found much cheaper used as well.
Tundra tracker
Of the common SteamVR trackers, this is the smallest and most compact one. Unlike the Vive trackers, they are distinctly square witha single "rib" extruding diagonally from the center. Like the Vive 3.0 tracker, they have a 7+ hour playtime and also power on and off without much fuss. They also tend to be sold a bit cheaper new compared to the Vive 3.0. The one downside is due to their smaller surface area, they tend to suffer some tracking jitter (as in they "wiggle" a bit) compared to the Vive trackers. Generally, this still good enough for general full body tracking for most people, although this can cause issues with continuous calibration and thus is not recommended for that purpose.
Sources and reviews