How To Maximize HTC Vive Play AreaApril 25, 2016 | vive htc room-scale play-area chaperon tracking
Vive roomscale is a glory to behold and a real revolution in gaming and immersion. In this report, we're going to follow up on the HTC Vive fitting guide and take a deep dive into Vive roomscale areas so you better understand what things like play area, chaperon, and tracking area really mean and how you can potentially improve your overall Vive experience with a solid grasp of roomscale fundamentals. We'll also talk about you can push the limits and go "beyond the grid".
This diagram will guide the rest of our discussion as it shows the relation of the roomscale areas of interest we will discuss:
Let's cover this one first because it is the one most talked about and on the spec sheet. The play area is the play area a VR game or application is guaranteed you can move within. It is also uniform in that it is either a rectangle or a square. This allows the game or application to customize itself to your available play area, but not necessarily limit you to it, which we will see is important later.
The play area determines the size of the gray area drawn at your feet during certain applications like the Lab or the base load environment. A useful tip is to move to the center of that area whenever you have the opportunity, such as during a load sequence, as this sets up in a good spot for the next experience and generally gives you the best tracking.
For example, in the Lab Longbow demo, it's best, especially if you have a small play area, to get on center before you load into the map room and then teleport up to the table and start the demo by touching the player icon in the toy castle without physically moving from the center of the play area until you are loaded into the castle. This allows you to roam your little tower fully even with a small play area instead of being up against the edge of the play area in one direction already.
The maximum size of the play area is approximately 13'x13'. It also cannot be any bigger than the next area we will talk about, the chaperon area and is determined by the largest rectangle that will fit in the chaperon area, up to 13'x13'. If your chaperon area is really big, you can choose exactly where the play area occurs within the chaperon area, but it will never be more than 13'x13'. However, "play area" is bit of misnomer because, well, watch what happens next.
Which brings us to the chaperon area. It's a little confusing because when you do roomscale setup and you run around with the controller marking out the confines of your play space, you may think you are marking the play area. However, you aren't doing that at all. What you are really doing is marking out the chaperon boundaries, which defines the blue cell grid that comes up when you get close to that boundary. The chaperon area is not limited to being a rectangle or square, but it must fit a square or rectangular play area within it.
If you think about this for a moment and realize that the chaperon area can be larger than your play area, it means that, if this is the case and you start walking towards the boundary of your play area, you can walk right out of the play area! Of course, this is only true as long as the boundary of the play area doesn't coincide with a physical wall in real life, in which case it will correspond with the chaperon area and you will see the chaperon grid before you hit it (hopefully).
The question that immediately arises is how can you make the chaperon area bigger than the play area when the spec calls for placing the light house stations at a maximum of 16'4" on the diagonal, which encompasses a maximum of a 13'x13' space? This is the point in this report where we go off the official tracks, because what I am going to describe next is definitely not in the manual. You see, "a maximum of 16'4" feet on the diagonal" is just words. Like the PC users we are, we will not sit idle and accept the spec as the final word! We'll see just how far the technology will go, which leads us to the Tracking Area.
The real question becomes how big of a chaperon area can we make? The answer to that question is, everywhere the headset and controllers can be tracked. For those to track, they need to be able to see the base stations. The base stations only have a 120-degree field of broadcast, which only covers a 13'x13' area when they are placed 16'4" apart, just because geometry. But when we push the base stations further apart, geometry helps us as the total tracking area grows quickly.
What's going to stop the expansion? Well, the obvious limiter is walls or other physical stuff that you can run into or occludes the sight line between the base station and headset/controllers, like your couch. Technically your controllers and headsets could be tracked above the couch, but, if you put the couch inside your chaperon area, you are going to be eating popcorn kernels out of the seat cracks with your (remaining) teeth when you encounter it blind while running in terror from the Lab fork lift (a story for another time). So we'll make an arbitrary rule here that the tracking area only includes all areas that are clear of all items from floor to ceiling, even if that is not literally true.
The second thing that will stop the expansion is when the base stations start to lose sync with each other, which will cause the headset and controller tracking to get confused. This happens somewhere over 16'4". But there is a secret weapon. Find the link cable in your Vive box. Consider its length. It is very, very long. So long, in fact, that even when you place the tracking stations 25' away from each other, there is enough link cable to reach the tracking stations from each other if you route the link cable along the full length of two walls to get there! Why is it this long? There can only be one explanation - the Vive is engineered to be potentially way more capable than HTC can officially let on.
The third thing that will stop expansion are environmental issues. Windows, strong light or infrared sources, and mirrors all seem from various user reports to have negative effects on tracking. The less optimal the environmental, the more likely problems will develop when you go out of official spec.
Lost In VR
So far, we assumed you set your chaperon boundaries at the maximum extent of your tracking area. But you don't have to. You could set them smaller than the actual tracked area, which you might willingly choose to do if the controllers do not track well in some far corner of the tracking area. What does this mean? It means that when the blue grid comes up, if there isn't a physical wall to stop you, you can walk right out of the chaperon area, too.
You should never do this, at least without someone to spot you, because at this point you are truly lost in VR. You have no reference and no boundaries. It's just a matter of time before reality catches up with you in a very painful way. Or you discover ISOs, man, ISOs.
Pushing The Limits
As an example, my base stations are approximately 25' apart, 8' off the floor. They are connected by the link cable with one base station channel set to A and the other b (very important as just plugging in the cable does not make the base stations link by cable). This lets me roam a room that is a little over 17'x19' feet, or over 320 square feet compared to the roughly 170 square feet of the play area and the official maximum spec. The headset and controllers track everywhere. Without the link cable, they do have issues in the corners without base stations
The most fun I have had in VR is when I first moved the base stations apart, didn't even bother to do roomscale setup again because I was so enthralled by the larger tracking area, got dangerously lost in VR, and quickly drew this terrible and massively anatomically incorrect rendition of an aquatic dinosaur skeleton for a friend's son.
This looks like a pre-kindergarten doodle in 2D (and 3D). I'm embarrassed. Here's the thing, though: It's 16' feet long. With a large enough tracking area, you can walk through the ribs from tip to tail, slightly ducking your head to avoid hitting the vertebrae.
I like that.
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