Saturday, 17 March 2018

Designing HoloLens Apps For A Small FOV

In my latest VRDC discussion I spent a slip speaking about constraints of the platform. The most common complaint about HoloLens and any other AR or MR platform is the little window where the augmentations appear. This very low FOV problem is a enormous problem of physics that’s unlikely to be solved based on Moore’s Law. Get used to it. We’re likely to be stuck with it for awhile. (Please someone prove me incorrect!))

It isn’t the end of the world. It’s only that programmers need to learn to create applications around this limitation.

GUIDE THE USER

Many VR applications require the consumer to look around. That’s the purpose of becoming immersed in a digital environment. Even if it’s a seated encounter, normally the player is invited to search the scene to get things to look at or interact with.

In mixed reality, the absence of peripheral vision (or anything close it) due to FOV constraints makes visually looking for objects frustrating. A quick scan of the scene won’t catch your attention something interesting, you need to appear more deliberately for stuff in the spectacle.

HoloLens’ provides a remedy for this with the course. This can be a directional indicator arrow connected to the cursor that points at the path of a targeted item.

Perhaps a more natural variant of this is used in Young Conker. The directional indicator is 3D, obviously sliding together and colliding with the environment.

USE AUDIO CUES

Unity makes it amazingly easy to add spatial audio into a HoloLens app. Just enable the Microsoft HRTF Spatializer plugin at the audio settings and look off “spatialize” on your positional audio sources. This is more than only a technique for immersion–the positional audio is so persuasive you can use it to direct the consumer’s attention anywhere in the environment. If the object is way out of the consumer’s view, emit a sound out of it to promote the player to look at it.

DESIGN ART ACCORDINGLY

Having art break the limited FOV framework is a real problem. To a certain level, this can’t be solved–have close enough to anything and it will be large enough to go beyond the FOV’s enhancement area.

Ether Wars uses little objects to Avoid breaking the framework

This is why I design many HoloLens games to work with a lot of smaller versions rather than large game titles or objects. If the item of interest to the consumer isn’t breaking the framework, he might not notice the Remaining images are getting trimmed. Also, Microsoft recommends maintaining the cutting airplane a few feet from the consumer–so if you’re able to design the game such that the player isn’t supposed to have close enough to the holograms, then you might be able to prevent most frame-breaking cases.

CONCLUSION

For AR/MR programmers, limited FOV is a fact of life. In enterprise apps where you’re focused on a specific task, it is not so bad. For games, most ordinary players will probably be put off if they have to wrestle a lot of with this limitation. Microsoft’s showcase games still play very well with this restriction, and reveal some creative methods of getting around it.