The HTC Vive Focus is a fascinating feature in the VR world. It eliminates the wires typically attached to the top headsets and preserves the six levels of freedom (6DOF) with no requirement for external tracking but at the expense of the capabilities of a full desktop computer.
HTC Vive headset has to be noted as being very comfortable, though the strap was hard to figure out at first, when it is properly adjusted the headset sits very comfortably on your head.
Image Source: Google
Developing for the headset
At its most basic, the Focus is an Android phone, you plug it into your computer like one, you deploy to it like one and you can access it like one (with the Android SDK’s Android Debug Bridge (ADB) tool).
Unity
The Vive Focus is used in Unity through an SDK package called Wave VR, this is HTC’s mobile VR package that looks like it supports more than just Focus for mobile VR purposes.
There is a Unity section in the documentation for it that has a section called ‘Unity Plugin Getting Started’ that is required reading. It will tell you what you needed:
1. Android SDK 7.1.1 (API level 25 or higher)
2. Android SDK Tools version 25 or higher
3. Unity Android Package
4. With the Android SDK and the JDK set up
5. Wave VR Unity SDK (it’s within the main Wave VR SDK download)
When you’ve imported the SDK, it helpfully comes up with a menu suggesting a few things, I’d suggest accepting them all.