At the CES 2018 (if you lost the news about it, read this post of mine where I summarize them all) HTC Vive has presented the Vive Pro, that has lots of fantastic features and among these ones, there is the use of SteamVR Tracking v2. All this talking about Vive and Vive tracking has made me willing to write an article about one of the things that most often people ask me about SteamVR tracking, that is:
- What is its maximum game area? What is the maximum size of the room-scale area?
- Can I use two or more Vives in the same room?
So I decided to write a little article to answer both these questions so that in the end you’ll be able to make a huge Vive party with lots of people in the same room playing together in VR!
NOTE 1: to understand completely this post, you should understand how SteamVR tracking works, so I recommend you read this related post of mine.
NOTE 2: this article regards SteamVR tracking v1.
Maximum game area
According to the manual, you have to put the Lighthouse stations at a maximum distance of 5m one from the other and this gives you an approximate maximum area of 3.5m*3.5m inside which you can play. It is always good to respect the rules that the manuals give you and this case is not an exception. Using the recommended settings guarantees that:
- The tracking works under optimal conditions;
- You use the setting that the developer is expecting for the game. If you could walk for a 50x*50m area when the dev expects something a lot smaller, you’d violate any assumption that the game designer has made and so the game you’re going to play is expected to become strange or unplayable (see for instance what has happened when I simulated a similar situation using the 3dRudder controller or the WalkinVR plugin).
So, be a good boy.
But… honestly, I’m not… I am a pirate, so I won’t let Valve telling me what I have to do 😀 . So, let’s try violating some rules.
First of all, you have to know that there are some tolerances in the above numbers: so it doesn’t happen that when you put the station 5.05m away, everything will stop working… so if you just need a bit more extra space, for sure you can start by putting the Lighthouse a bit further apart and see if the setup still works. Some users report having gained some space by just trying to move the stations apart.
But if you need mooore space, we have to start understanding why there is the above limitation: it seems that it is mainly because of the sync between the stations. If the stations are too far away one from the other, they can’t sync properly because they can’t “see” each other, so everything will stop working. To solve this, we can use the alternative way of syncing that these devices have, that is the cable. HTC kindly provides all Vive owners a cable to keep the Lighthouses in sync when there are problems with the optical sync. It seems that the cable is longer than the recommended 5m… and one of the reasons is that it can allow for bigger distances between the stations.
In fact, using the cable it is possible to reach bigger distances: one user reported putting the stations 7.5m one from the other and a group of crazy guys has also managed to put them more than 8 meters apart, using a wireless communication to avoid the cable being inside the play area! That’s insane!
So, the trick is: plug the “sync cable” into both the stations and set one base station to channel “A” and the other to channel “b”. Then move the stations far apart until you obtain your desired game area. Launch SteamVR room configuration and then… have fun 🙂
UPDATE: Rob Cole from “Proof R&D Ltd” in London has contacted me after reading this article to talk me about the experiments he made himself about obtaining a huge space for its HTC Vive with a setup he called “Vive Roomscale Plus”. During his crazy experiments that he detailed me, he obtained to put the Lighthouses MORE THAN 9 METERS APART! And he said that at that distance, playing games like Space Pirate Trainer or The Lab was something really incredible. He also tried to increment further the distance, but the tracking started becoming too glitchy.
The laser cast by the stations is powerful enough to cover such distances: I guess that you may anyway have more interferences issues and also less precision (more noise) in tracking…. you’re using a non-recommended setting, after all! But… as far as I can see… it is very cool!
Multiple Vives in the same room
Ok, now you have a very big tracking area. Is it then possible to play with your friends in the same area? Yes, it is.
First of all, we have to understand what you do mean with “Multiple Vives in the same room”: do you mean that they’re attached to the same PC? And has every headset a pair of Lighthouse stations associated? Let’s see al possible cases.
1 PC, 2 Lighthouse stations, multiple Vives
This is a tricky situation: you have a PC with 2 Lighthouse stations attached and you want more people to play VR, each with a personal headset attached to the same PC. First of all, I want to compliment with you for the confidence in the computational power of your PC… because to run multiple VR games at 90 FPS you really need a monster PC. Furthermore, you need a bazillion HMDI and USB ports. After these compliments, I have to say you that unluckily this is not a valid configuration: every PC running SteamVR can have only one single Vive attached.
But… but… there is a trick that we pirates hand down generation to generation: you can use virtual machines. That is, your monster PC may run as many virtual machines as the number of connected Vive devices. This way every virtual PC is connected to only one Vive and everything works like a charm.
But you really need a super-expensive PC to do this kind of nerdy stuff: months ago, NVIDIA announced a PC dedicated to doing something like that: it featured four Quadro P6000 GPUs to be connected to four Vive Professional Edition, so that to create a collaborative VR environment. Do you want to know the price? Well, I’ll just tell you that a single Quadro P6000 is worth $5000…
I’m not meaning that you have to spend necessarily that crazy amount of money, but surely you need a very powerful PC to do this kind of operation.
Multiple independent stations (PC + Vive + 2 Lighthouse Stations)
In this case, every user has its own set of hardware: his PC, his Lighthouse stations, his VR headset and controllers. This seems the most simple setup of all: if I’m playing with my setup and you’re playing with your setup, every one of us should be able to play independently. But don’t forget that the two users are inside the same room: this means that you have multiple Lighthouse stations casting rays and sync flashes all around the room, so the headset of user A may be hit by the Lighthouse rays of the stations of user B and everything would get crazy. Do you remember when I said that Lighthouses’ lasers are pretty powerful? Well, in this case, this is not a good news. It is even reported that in exhibitions, the Vive stations of one booth sometimes have caused interferences with the installation of another booth!
So, what is the solution in this case? If your setup shows interferences, the only solution is: use a wall, or whatever you have to separate the two installations, so that to shield each installation from the rays of the other. This is what they do in arcades, for instance.
But, ehm… beware of the type of wall that your using: I’ve found a user inside Vive forums to which two separate installations were still able to interfere each other! As a Vive Staff member answered him:
The partitions need to be made of material that is completely opaque to ~850nm IR light. The lasers that the basestations emit are pretty powerful and one possiblity is that they’re penetrating the partition or are bouncing off surfaces such as the floor. IR light interacts with materials so differently than visible light that these types of issues can be hard to diagnose without knowing what types of materials are in your environment.
So, ask your bricklayer to build a wall that is opaque to 850nm IR light. And hope that he won’t punch you in the face for such a strange request.
2 Lighthouse stations, multiple PC+Vive
This is a hybrid case: every user has his own PC with his own Vive and controllers, but they all share the same couple of Lighthouse stations. How is it possible? Well, if you’ve read my post on SteamVR tracking, you should now know that the Lighthouse stations are just two dull light emitters. The headsets and controllers get the light from them and understand their position in space, but they absolutely don’t care if these light data are read from other devices, too. This is the simplest situation of all: you just attach the headsets, configure the play areas and then play together, like these very thin guys do.
If you want a step-by-step guide, you can find it in the Vive Forum link provided above:
1) Prepare your play space with the two lighthouses
2) Connect the headset to your first PC; run room-scale setup in SteamVR
3) Quit SteamVR on the first PC to power down the headset and controllers
4) Connect the headset to your second PC; run room-scale setup in SteamVR
5) When you restart SteamVR on the first PC, it should detect the lighthouses and pair correctly.
And that’s it. The only problem you can have is one player that for one reason or another (e.g. he’s jumping) occludes the IR rays so that they don’t reach the other player… but you can put the stations high enough for this to happen only seldom.
The only thing you have to take really in count is how to setup the Chaperone areas of the two players. The smartest choice is to set two non-overlapping gaming areas, so the two players can play together safely. But you may also want to make the two areas overlapping or even coincident, if you want the two players to interact between them virtually while they also ineract physically: notice that this may be cool, but can also cause safety issues (one player running over the other or punching him).
So, you may ask: how many players can play concurrently using this method? Theoretically, as many as you want: I’ve read people that managed to make it work even for five concurrent people! I guess that the room has become a bit crowded that day…
As you can see, following just some rules it is possible to make a little HTC Vive party! I’ve sad that these rules regard SteamVR v1 because in v2 everything will change: there will be fewer interferences, more lighthouse stations allowed and hence a bigger tracking area. This will be possible because the headset will be able to detect the station which has emitted the light it is receiving. The general spirit of this article should remain valid, but there will be some differences.
Hope you enjoyed this little tutorial: if this is the case, please share it on your social media channels and subscribe to my newsletter!
(Header image by VR Scout)
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