rt-xr sentient space visualization now on iOS!

I have to admit, I am in a state of shock right now. For some reason today I decided to try to get the rt-xr Viewer software working on iOS. After all, it worked fine on Windows desktop, UWP (Windows MR), macOS and Android so why not? However, I expected endless trouble with the Manifold library but, as it turned out, getting it to work on iOS was trivial. I guess Unity and .NET magic came together so I didn’t have to do too much work once again. In fact, the hardest part was working out how to sort out microphone permission and that wasn’t too hard – this thread certainly helped with that. Avatar pose sharing, audio sharing, proxy objects, video and sensor feeds all work perfectly.

The nice thing now is that most (if not all) of the further development is intrinsically multi-platform.

Sentient space sharing avatars with Windows desktop, Windows Mixed Reality and Android apps


One of the goals of the rt-ai Edge system is that users of the system can use whatever device they have available to interact and extract value from it. Unity is a tremendous help given that Unity apps can be run on pretty much everything. The main task was integration with Manifold so that all apps can receive and interact with everything else in the system. Manifold currently supports Windows, UWP, Linux, Android and macOS. iOS is a notable absentee and will hopefully be added at some point in the future. However, I perceive Android support as more significant as it also leads to multiple MR headset support.

The screen shot above and video below show three instances of the rt-ai viewer apps running on Windows desktop, Windows Mixed Reality and Android interacting in a shared sentient space. Ok, so the avatars are rubbish (I call them Sad Robots) but that’s just a detail and can be improved later. The wall panels are receiving sensor and video data from ZeroSensors via an rt-ai Edge stream processing network while the light switch is operated via a home automation server and Insteon.

Sharing is mediated by a SharingServer that is part of Manifold. The SharingServer uses Manifold multicast and end to end services to implement scalable sharing while minimizing the load on each individual device. Ultimately, the SharingServer will also download the space definition file when the user enters a sentient space and also provide details of virtual objects that may have been placed in the space by other users. This allows a new user with a standard app to enter a space and quickly create a view of the sentient space consistent with existing users.

While this is all kind of fun, the more interesting thing is when this is combined with a HoloLens or similar MR headset. The MR headset user in a space would see any VR users in the space represented by their avatars. Likewise, VR users in a space would see avatars representing MR users in the space. The idea is to get as close to a telepresent experience for VR users as possible without very complex setups. It would be much nicer to use Holoportation but that would require every room in the space has a very complex and expensive setup which really isn’t the point. The idea is to make it very easy and low cost to implement an rt-ai Edge based sentient space.

Still lots to do of course. One big thing is audio. Another is representing interaction devices (pointers, motion controllers etc) to all users. Right now, each app just sends out the camera transform to the SharingServer which then distributes this to all other users. This will be extended to include PCM audio chunks and transforms for interaction devices so that everyone will be able to create a meaningful scene. Each user will receive the audio stream from every other user. The reason for this is that then each individual audio stream can be attached to the avatar for each user giving a spatialized sound effect using Unity capabilities (that’s the hope anyway). Another very important thing is that the apps work differently if they are running on VR type devices or AR/MR type devices. In the latter case, the walls and related objects are not drawn and just the colliders instantiated although virtual objects and avatars will be visible. Obviously AR/MR users want to see the real walls, light switches etc, not the virtual representations. However, they will still be able to interact in exactly the same way as a VR user.

Using Unity and Manifold with Android devices to visualize sentient spaces

This may not look impressive to you (or my wife as it turns out) but it has a lot of promise for the future. Following on from 3DView, there’s now an Android version called (shockingly) AndroidView that is essentially the same thing running on an Android phone in this case. The screen capture above shows the current basic setup displaying sensor data. Since Unity is basically portable across platforms, the main challenge was integrating with Manifold to get the sensor data being generated by ZeroSensors in an rt-aiEdge stream processing network.

I did actually have a Java implementation of a Manifold client from previous work – the challenge was integrating with Unity. This meant building the client into an aar file and then using Unity’s AndroidJavaObject to pass data across the interface. Now I understand how that works, it really is quite powerful and I was able to do everything needed for this application.

There are going to be more versions of the viewer. For example, in the works is rtXRView which is designed to run on Windows MR headsets. The way I like to structure this is to have separate Unity projects for each target and then move common stuff via Unity’s package system. With a bit of discipline, this works quite well. The individual projects can then have any special libraries (such as MixedRealityToolkit), special cameras, input processing etc without getting too cute.

Once the basic platform work is done, it’s back to sorting out modeling of the sentient space and positioning of virtual objects within that space. Multi-user collaboration and persistent sentient space configuration is going to require a new Manifold app to be called SpaceServer. Manifold is ideal for coordinating real-time changes using its natural multicast capability. For Unity reasons, I may integrate a webserver into SpaceServer so that assets can be dynamically loaded using standard Unity functions. This supports the idea that a new user walking into a sentient space is able to download all necessary assets and configurations using a standard app. Still, that’s all a bit in the future.

Google’s WorldSense

Lenovo just announced the Mirage Solo VR headset with Google’s WorldSense inside-out tracking capability. The result is an untethered VR headset which presumably has spatial mapping capabilities, allowing spatial maps to be saved and shared. If so, this would be a massive advance over ARKit and ARCore based AR which makes persistence and collaboration all but impossible (the post here goes into a lot of detail about the various issues related to persistence and collaboration with current technology). The lack of a tether also gives it an edge over Microsoft’s (so-called) Mixed Reality headsets.

Google’s previous Tango system (that’s a Lenovo Phab 2 Pro running it above) did have much more interesting capabilities than ARCore but has fallen by the wayside. In particular, Tango had an area learning capability that is missing from ARCore. I am very much hoping that something like this will exist in WorldSense so that virtual objects can be placed persistently in spaces and that spatial maps can be shared so that multiple headsets see exactly the same virtual objects in exactly the same place in the real space. Of course this isn’t all that helpful when used with a VR headset – but maybe someone will manage a pass-through or see-through mixed reality headset using WorldSense that will enable persistent spatial augmentation using a headset with hopefully reasonable cost for ubiquitous use. If it was also able to perform real time occlusion (where virtual objects can get occluded by real objects), that would be even better!

An interesting complement to this is the Lenovo Mirage stereo camera. This is capable of taking 180 degree videos and stills suitable for use with stereoscopic 3D displays, such as the Mirage headset. Suddenly occurred to me that this might be a way of hacking a  pass-through AR capability for Mirage before someone does it for real :-). This is kind of what Stereolabs are doing for existing VR headsets with their ZED mini except that this is a tethered solution. The nice thing would be to do this in an untethered way.

YAXRH – this time a Samsung Odyssey Windows MR headset

This Samsung Odyssey Windows MR headset just arrived and it is really quite good. The earlier developer’s HP headset didn’t have the motion controllers so a HoloLens clicker (or Xbox controller) had to be repurposed for meaningful interaction. The motion controllers are really kind of fun and it’s totally spooky to watch the virtual joysticks move all by themselves when you adjust the real joysticks. The built in sound is another great advantage. It makes the headset somewhat bulky but the benefit is great spatial sound. The images are pretty good too although you do have to get the headset positioned correctly for optimum quality. Once you do, there’s not too much chromatic aberration in a fairly reasonable central area. The distance between the lenses is also adjustable which is another assist in getting good visual quality. The display certainly has the usual screen door effect but it isn’t really very offensive and resolution seems very acceptable. On the negative side, the display does not flip up (well it does once if you push hard enough 🙂 ) which is a bit of a negative while developing software where it is sometimes handy to go back and forth to a desktop display.

It’s kind of fun to open up the desktop and look at the MR Portal there so you can get the classic video feedback effect. I tried watching some movie trailers – not too bad. I then tried a game called Rock and Rails. Yes, well, that didn’t last too long. Instant vertigo and motion sensitivity – these things are just too immersive!

Anyway, a worthy addition to to the growing pile of headsets here.

My day with Windows Insider Preview, Unity 2017.2.0b8 and Windows Mixed Reality Headset

Yes, I am drinking a beer right now – it has been a long day. Mostly I seemed to spend it nursing Windows through its upgrade to the latest Insider Preview (16257) and begging the Insider Preview website to allow me to download the Insider Preview SDK which seemed to require all kinds of things done right and the wind blowing in the right direction at the same time.

The somewhat bizarre screen capture above is from a scene I created in the default room. The hologram figures are animated incidentally. What I mostly failed to do was to get existing HoloLens apps to run on the MR headset as Unity kept on reporting errors when generating the Visual Studio project for the apps, after having performed every other stage of the build process correctly. Very odd. I did manage to get a very simple scene with a single cube working ok, however.

Then I went back to the production version of Windows (15063) and tried things there. Ironically, my HoloLens app worked (apart from interaction) on the MR headset using Unity 5.6.2.

Clearly this particular Rome wasn’t built in a day – a lot more investigation is needed.