Acer Windows Mixed Reality hands-on
I’ve recently had a chance to play with a Windows Mixed Reality headset developed by Acer.
As I’ve said in previous posts Windows Mixed Reality is Microsofts major entry into Virtual and Augmented Reality. Like other Microsoft products, it is an open platform designed to allow 3rd party developers to create hardware, rather than a priorietary piece of hardware. ACER are one of the developers of Windows MR headsets, and I’ve previously talked about the design of the headset.
There have been lots of reviews of the headset, so I want to focus more on how it relates to what we have taught in our VR course and in particular development.
Design of the HMD
As you can see from the images, the overall design of the HMD is quite different from other HMDs like the Oculus Rift and HTC VIVE. For one thing it is more colourful with a nice blue front.
Also notable is the single large rigid band that goes around your head. Its very different from the multiple, soft straps of other headsets, but its comfortable to wear and easier to adjust with a turn wheel at the back.
One nice feature is that the visor of the headset can be lifted up without taking the headset off. This is a very useful, particularly for development, when you move in and out of VR a lot to code and test.
There are also two cameras on the front of the headset, like all Windows MR HMDs, but I will come to that later.
The HMD comes with two motion controllers that follow the standard design of Windows MR controllers, which is the same for all manufacturers. They look a bit like a cross between the Oculus Touch and VIVE controllers. They a big circular band around the top similar to the Touch (and for the same reasons, to make tracking easier), but in generally they are more stick shaped like the VIVE. One feature I like is that they have a side “grip” button that is for gripping and picking things up, which could feel a lot more natural than a trigger in a lot of situations (and so increase plausibility illusion).
Inside-Out Tracking
The really big innovation is due to the cameras on the front that I mentioned earlier. Windows MR supports Inside-Out tracking.
That means that, rather than having external cameras tracking the HMD like the Rift or VIVE, the headset tracks itself, using the front facing camera, by tracking its movement relative to the external environment. This is a much harder computer vision problem (involving the famous SLAM technique), but it seems to handle it very well. The tracking seems just as good as the Rift and VIVE with their external cameras.
Inside-out tracking has some major advantages, apart from the simple fact that you don’t need extra camera hardware. The set up is much easier, you don’t need to calibrate cameras (though you still need to define a safe waling area if you are going to move around). You can much more easily set up the headset in new spaces. Also you aren’t limited by the range of the camera, which means you can have quite a wide space. You don’t loose tracking suddenly because you step out of the view of the cameras, and you can’t mess up all the tracking by knocking a camera out of place, as I did this afternoon :(
The front cameras also track the controllers, which also works well, they track smoothly and naturally. One drawback is that the controllers are only tracked properly when they are visible to the cameras. This is normally OK because the cameras pretty much correspond to what you can see, so if the controllers aren’t being tracked you won’t see it. Even when they are out of range, they track for a bit (presumably with dead reckoning) and will still continue to rotate properly because they have gyroscopes, so you can still point to things.
The situation where I think this could be a drawback is in Social VR. You can’t see that your hands aren’t moving properly when you don’t look at them, but other people will be able to. Also, virtual mirrors won’t work properly, and they are an important part of creating the Embodiment Illusion.
So I think this is still a challenge for inside-out headsets, how to track controllers anywhere, but I hope it is solved because inside-out is potentially so much better than using external cameras.
Anyway, I think having working inside-out tracking is a very impressive achievement on the part of Microsoft and ACER, and they deserve to be praised for getting there well ahead of the other manufacturers.
Mixed Reality
The other big potential advantage of having front facing cameras is hinted by the name: Mixed Reality.
Mixed Reality is a continuum between Virtual Reality and Augmented Reality (and onwards until you reach just normal reality. Augmented Reality is about having virutal objects in the real world and VR is about having an entirely virtual world. The idea of a mixed Reality continuum was introduced by Paul Milgram:
Mixed Reality is about having a single platform that can do both and lots of things in between, for example, having real world objects or real people in a virtual world, something that Milgram called Augmented Virtuality.
There has been some hype about competition between VR and AR, but, as I’ve said before, I think it the idea is very silly. Part of it is that they are good for very different things, so they are not really in competition. But Windows MR shows that you can use the same technologies to implement both VR and AR, and if you do, you get things like Augmented Virtuality for free.
So if Windows MR succeeds, VR and AR will really not be in competition, because if you get access to one, you will have access to the other. That means that you can choose the one that best fits the tasks you are doing, and I think people will find that they each suit very different tasks.
Unfortunately, for now the software available is very focused on VR, but I hope that we will be exploring the full continuum soon.
Getting Started
Getting started using Windows MR is very easy. When you first plug the device into your computer (via HDMI and USB3 connectors), a screen will pop up to guide you through the set up process.
It is all very straightforward. My only problem was with Bluetooth. The controllers communicate using Bluetooth, and I didn’t realise that my PC did not have a Bluetooth card :( So I had to make a run to the shop for a USB bluetooth dongle and that took a bit of time to set up, so the controllers were tricky, but that was very much a problem with my PC, I’ve tried it on an ACER laptop and it works like a dream.
Developing for Windows MR
So what is it like to develop for Windows MR?
I had a go at porting some of my projects to Windows MR, and I have to say this is where Unity is great. You can take a project developed in Unity for one platform and make it work on another platform with very little effort at all.
What you need to do is go to File->Build Settings and select the “Universal Windows Platform” option.
As you can see from the above screenshot, you are likely to need to download and install the module, but that is simple, just click on the button.
Once it is installed, you can adjust the settings for the platform, on the left on the image below.
You don’t need to change much, just make sure that the settings match the instructions below:
You also need to select Player Settings->XR Settings and choose Virtual Reality Supported (on the right in the image above).
Once you have changed all of those settings, you can select “Build And Run” from the Build Settings Dialog. Once you have done that once, you can just press play and it will run in your headset.
Learning Windows MR Development
One of the best ways of learning a new platform is to look at real examples of projects. Ideally, platform developers provide tutorial projects that guide you through specific features. Microsoft have done very well at this, having released a Mixed Reality ToolKit that includes lots of assets for using Windows MR and also example projects:
Unfortunately, it doesn’t seem to be on the Unity Asset Store, but you can download it from GitHub on the link above.
It is a complete Unity project that includes a lot of individual scenes, each of which shows how to use a particular feature of Windows MR.
This is a great resource for learning Windows MR, so I would really recommend that you start by understanding some of the examples.
Summary
Windows MR looks like a great platform for VR and significantly, more than VR. I think that in future the Mixed Reality possibilities will be very powerful, but for now it is a good VR platform that uses Inside-Out tracking to avoid a lot of the set up overheads of other 6DOF VR HMDs.
I also really like the ACER headsets. They show an innovation in design and both easy and comfortable to use.
