Review: HoloLens

I have now used Microsoft HoloLens for some months. The original reason to have the device was our Sm4rtLab, but I have also done some other testing. Here my experience and opinions.

HoloLens is a new way to combine real world with virtual object; this is called Mixed Reality (MR). So, when one wears HoloLens, the surrounding world can be seen, but there can be added some virtual object. In the way that they keep their positions even when the observer is moving.

With virtual reality devices one will be isolated from the external world which can case unpleasant feeling. With HoloLens there is not that problem. On the other hand, with typical augmented reality glasses the additional information is like a transparent screen which moves together with the observer. But in HoloLens, the objects are not fixed with respect the observed but the surrounding.

HoloLens is an independent device. So, not just the display for something, but it includes itself Windows 10 computer. It is a bit big to wear, but not too heavy. The batter lasts 2-3 hours.

To enable mixed reality, HoloLens uses its sensors to map the room and making a 3D model of it. Then, the position and the orientation of HoloLens is measured continuously, and the virtual object are then placed in the view correctly according to this information.

Most of time the mapping of the surrounding works reasonably well. And what is nice, HoloLens remembers the rooms. So, if I insert some object into my office, they will be there even in the next time I use HoloLens.

To gaming HoloLens bring a totally new aspects. Especially Robo Raid has managed well to integrate the virtual robo enemies to one’s surrounding; they really look like hitting holes to the walls and penetrating through them.

The game works smoothly. It shows that one can make smoothly working software to HoloLens even though my skills are not good enough for that.

Some other software is also available for HoloLens. Mostly in the demo level. One can inspect the Solar system or human body.

HoloAnatomy is rather nice education software; one can inspect human body in full scale. And to inspect the details, just walk closer.

I also tested Skype for HoloLens. And that was a disappointment! HoloLens does not have good multitasking. So, I can not have multiple programs open. Especially with Skype that stupid: If I call someone, I can not see any other software. Stupid.

Also there where one “funny” feature in Skype: when my friend shared his desktop with me in Skype, I saw a mirror image of it. Funny, but not very practical…

The main limitation in HoloLens is the field-of-view. If you have watched videos on HoloLens view, you would be surprised that the clipping takes the place.

The reason is very simple: Our own field-of-view is quite broad. But making a see-through display causes limitations. It is based on waveguides and diffractive gratings, and those sets some physical limitations.

Also the view is quite sensitive on how one wears HoloLens. Sometimes it is even difficult to see even the limited full view. Calibration of the device for own eyes helps a bit. But even then sometimes it is fighting with correct view.

However, this version is for developers to enable starting the application development. The customer version is coming later; hopefully with broader field-of-view and color reproduction.

I have also made myself some simple software for HoloLens. Testing how I can bring 3D object into it. For example, for educational purposes.

The software development is quite simple: One needs Unity software development tools (I downloaded free personal edition) with HoloLens SDK. Then, one needs Visual Studio.

So, first I created 3D scene in Unity and build the project. Some special tricks are needed, but those can be easily found in internet. Then, I opened the build in Visual studio, did some small tricks again, connected the computer to HoloLens with USB, and deployed the application into HoloLens. Once all is clear, the whole project takes takes just minutes.

Here is one example I did: Some simple 3D models of crystal structures. And 3D model of my head with them..

As one can see, the operation is not very smooth. When I moved, the model was not able to follow me smoothly. But I think that this is the problem of my skills and Unity since Robo Raid seemed to work well.

Of course, making more complicated software I will leave for the experts. Like our Sm4rtLab that was build by Process Genius.

HoloLens has some features that makes demonstrations easier. First, one can easily take a photo or a video of the view; the examples above are made with that. Also, when HoloLens is connected to Microsoft account, the photos and videos will go automatically to OneDrive.

The second nice feature is the possibility to stream the view to pc. For that one should install HoloLens app to pc. Note that at the moment it is possible only if the region setting in pc is US. One can then connect HoloLens to pc and stream video and control the device. I have then connected pc to a projector to enable the presentations for larger groups.

One minor drawback in streaming is the latency is large – about one second. It uses wifi connection; normally I use a shared wifi from my mobile to make this connection. If there are more devices connected to wifi at the same time, the streaming can easily “freeze”.

Streaming works also with my Lumia mobile phone – HoloLens is available also for that. Funny detail.

As a conclusion: HoloLens is very interesting device. Brings entirely new world around us. A lot of possibilities, also in education. Also, starting to develop own software is simple enough even for me.

Some improvement is still needed: The field-of-view is too narrow and the price is too high.

And what pleases me: In the development HoloLens there are several researcher to whom I have taught optics.