HTC VIVE Wrist Tracker Instruction Manual

HTC VIVE Wrist Tracker
Developer Guidelines
Ver. 1.1

Version Control
Version Number Version Date Version Reason
1.0
20
22
.01.1
3
Initial version
1.1
2022.03.
30
Content update
©2019 HTC Corporation. All Rights Reserved. HTC, the HTC logo, VIVE, the VIVE logo, and
all other HTC product and services names are the trademarks or registered trademarks of HTC
Corporation and its affiliates in the U.S. and other countries.

Contents
Contents ................................................................................................................................. 1
Introduction ............................................................................................................................ 1
Use cases ....................................................................................................................................... 1
Hardware requirements .......................................................................................................... 3
Interface .......................................................................................................................................... 3
Radio frequency (RF) ...................................................................................................................... 3
Power ............................................................................................................................................. 4
Optics ............................................................................................................................................. 4
Mounting ......................................................................................................................................... 8
Mechanical specifications .................................................................................................... 12
Dimensions and weight ................................................................................................................. 13
Mounting base assembly .............................................................................................................. 15
Software ............................................................................................................................... 17
Accessory integration .................................................................................................................... 17
System requirements .................................................................................................................... 19
Data formats ................................................................................................................................. 19
Unity integration ............................................................................................................................ 22
Setting up Unity for content creation ............................................................................................. 23
Configuring the VIVE Input Utility (VIU) ......................................................................................... 27
FAQs .................................................................................................................................... 32

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
1 HTC Confidential and Proprietary
Introduction
This document provides development guidelines for VR accessory makers and content
developers interested in VIVE Wrist Tracker. These guidelines describe how to use VIVE Wrist
Tracker for position tracking and data transmission.
When paired with VIVE Focus 3, VIVE Wrist Tracker transmits tracking data wirelessly from
the tracker to the VIVE Focus 3 headset.
VIVE Wrist Tracker can also be attached to a peripheral accessory for object tracking. When
used for object tracking, VIVE Wrist Tracker transmits tracking data just as it does when used
to assist hand tracking. In addition, the accessory can also be connected to VIVE Wrist tracker
through its USB interface to obtain additional data from the accessory, which can then transmit
the additional data to VIVE Focus 3 along with the tracking data.
Use cases
There are three use cases for VIVE Wrist Tracker.
Use case 1: VIVE Wrist Tracker is attached to the wrist to assist hand tracking in VR. In this
scenario, VIVE Wrist Tracker is paired wirelessly with VIVE Focus 3 to transmit tracking data.
Figure: Use case 1

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
2 HTC Confidential and Proprietary
Use case 2: VIVE Wrist Tracker is attached to an accessory for object tracking. As with the
first use case, in this scenario, VIVE Wrist Tracker is paired wirelessly with VIVE Focus 3 to
transmit tracking data.
Figure: Use case 2
Use case 3: VIVE Wrist Tracker is attached to an accessory for object tracking. In addition, in
this scenario, the accessory is also connected to VIVE Wrist Tracker via USB, allowing the
accessory to send additional data to VIVE Wrist Tracker, which can then transmit the additional
data to VIVE Focus 3 along with the tracking data.
Figure: Use case 3

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
3 HTC Confidential and Proprietary
Hardware requirements
This section describes the hardware requirements for accessories used with VIVE Wrist
Tracker.
Accessories must meet specific requirements to ensure that VIVE Wrist Tracker can generate
accurate tracking data for the accessory and to ensure that any additional data provided by the
accessory is compatible with VIVE Focus 3.
Interface
1. USB Type-C port: USB 2.0 Full-Speed (client)
2. Buttons:
 Power button: Powers the tracker on and off
 App button: Defined by developer
Radio frequency (RF)
To ensure the stability of the wireless connection between VIVE Wrist Tracker and VIVE Focus
3, the OTA performance of the tracker must not degrade by more than 3 dB an accessory is
attached.
Please adhere to the following recommendations to maximize RF performance.
Figure: Spherical radius of the tracker antenna. Metal parts in this area may cause RF
interference. (Spherical radius = 30 mm, with the center being the antenna feed point.)

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
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For optimal OTA performance, the tracker antenna should be at least 30 mm away from
any metal parts.
Power
 USB Type-C port voltage requirement: 5V+/-5%; > 200 mA
 Maximum required charging time: 2 hours
Optics
VIVE Wrist Tracker has an asymmetrical shape. Therefore, its FOV is also asymmetrical. In
addition, VIVE Focus 3 uses inside-out tracking, so the FOV of the tracker depends on the
position of the headset relative to the orientation of the tracker. The following figures illustrate
the FOV of VIVE Wrist Tracker in relation to VIVE Focus 3 when the headset is about 50 cm
away from the tracker’s geometric center.
Figure: Tracker FOV relative to headset position along the sagittal plane

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
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Figure: Tracker FOV relative to headset position along the transverse plane
The headset must stay within the FOV of the tracker during operation. In addition, make
sure there aren’t any objects between the tracker and the headset, as this will interfere with
object detection.

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
6 HTC Confidential and Proprietary
The following illustration shows the FOV of VIVE Wrist Tracker when attached to a VR
gaming peripheral, in this case an imitation firearm. If the mounting base extends beyond
the recommended placement area, the tracker’s FOV will be blocked by the body of the
accessory.
Figure: Mounting base extends beyond recommended placement area
For optimal tracking performance, we recommend attaching the tracker to the accessory
so that the Power button faces the headset.

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
7 HTC Confidential and Proprietary
To maintain optimal tracking performance, make sure the gray area illustrated in the
following figure remains exposed during operation. Do not attach objects to it or cover it
with any materials.
Figure: Exposed area (gray) and contact area of VIVE Wrist Tracker when attached to an
accessory (blue)

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
8 HTC Confidential and Proprietary
Mounting
Adhere to the following guidelines to ensure your safety when using VIVE Wrist Tracker with
an accessory.
a. The specifications of the accessory’s mounting interface must match those of the
mounting base attached to the tracker.
b. The tracker should be easy to attach and detach with two hands (that is, with one
hand holding the tracker and the other holding the accessory.)
c. The user should not be at risk of physical harm while attaching or detaching the
tracker.
d. Attaching or detaching the tracker should not cause the user any discomfort.
e. To prevent unintended damage to the tracker, the tracker should not come into
contact with any external objects during operation.
f. To ensure optimal tracking performance, the accessory or its components should not
be in the tracker’s FOV.

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
9 HTC Confidential and Proprietary
Example mounting interfaces
Attaching VIVE Wrist Tracker to VR peripherals is simple and straightforward. The following
CAD drawings show examples of how VIVE Wrist Tracker can be mounted to accessories
such as imitation gaming weapons and safety equipment. The imitation gaming firearms
depicted are equipped with a Picatinny rail, which can be used as a mounting interface.
VIVE Tracker can be mounted to a Picatinny rail using a rail mount–type mounting base. CAD
drawings of the VIVE Tracker rail mount are available to developers. Contact us for more
information.
Imitation firearms (mounting interface: Picatinny rail)
Figure: Toy like gun with VIVE Wrist Tracker and rail mount-type mounting base

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
10 HTC Confidential and Proprietary
The following two figures show the schematics for the accessory mounting rail (Picatinny rail).

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
11 HTC Confidential and Proprietary
Imitation edged gaming weapons
The mounting interface should be as close as possible to the grip area of an edged gaming
weapon. The length of the gaming weapon should be defined in the VR program.
Fire extinguisher
When VIVE Wrist Tracker is attached directly to a grip, the tracker’s FOV must be free from your
hands and other objects during operation.

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
12 HTC Confidential and Proprietary
Mechanical specifications
The following specifications may be useful for determining the compatibility of VIVE Wrist
Tracker with various accessories.
Figure: VIVE Wrist Tracker

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
13 HTC Confidential and Proprietary
Dimensions and weight
Figure: Front, side, and back views of VIVE Wrist Tracker
The tracker measures 86.9 mm (L) × 45.0 mm (W) × 58.8mm (H) and weighs 48.1 g.

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
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Components
Figure: Components
1. LED indicators: Indicate pairing status
2. Power button: For powering the tracker on and off
3. App button: Defined by content
4. Mounting mechanism:
4.1 Metal pin for fastening accessories
4.2 Friction pad for preventing slippage between the tracker and an accessory
5. USB-C port: For connecting the tracker to an accessory
5. USB-C port
3. App button
1.
LED indicators
4.1 Metal pin
4.1 Metal pin
2. Power button
4.2 Friction pad

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
15 HTC Confidential and Proprietary
Mounting base assembly
The following drawing illustrates how to attach a mounting base to VIVE Wrist Tracker. CAD
files for the mounting base are available to developers. Contact us for more information.
Figure: Mounting base assembly
Make sure to install the mounting base on VIVE Wrist Tracker before attaching the tracker to
the mounting interface on the accessory.
Mounting base
Metal pin screw
Metal
pin screw
Metal pin
Metal pin

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
16 HTC Confidential and Proprietary
Metal pin dimensions
The following schematic shows the dimensions of the metal pins. (Unit: mm)

VIVE Wrist Tracker
HTC Corporation
Developer Guidelines
v1.1
2022/3/24
17 HTC Confidential and Proprietary
Software
This section describes how software can be used to adapt accessories and develop content for
VIVE Wrist Tracker.
In addition to transmitting tracking data, the VIVE Wrist Tracker can transmit additional data to
VIVE Focus 3 USB from an attached accessory through the tracker’s USB Type-C interface.
Accessory makers can utilize this feature when adapting accessories for VIVE Wrist Tracker.
For details on the data formats that can be transferred between an accessory and VIVE Wrist
Tracker, see the Data Formats section.
Content developers can also take advantage of this feature when designing VR content for
accessories attached to VIVE Wrist Tracker. For details on the types of software applications
that can be used for development, see the Accessory integration and Unity integration.
Accessory integration
This section provides information on position transformation between an accessory and VIVE
Wrist Tracker. Content developers can determine the correct rotation and translation result of
the content developed for the accessory in a game engine such as Unity.
The local coordinate system of the accessory is assumed to be front-facing on the z-axis (left-
handed coordinate system) with VIVE Wrist Tracker attached to the accessory as illustrated
below. The rotation degree and translation distance of an accessory in relation to VIVE Wrist
Tracker are described in terms of roll, yaw, and pitch, as well as Dx, Dy, and Dz, respectively,
during integration.
After the center of an accessory has been determined during the design process, the rotation
degree and translation distance can be measured according to the conditions of integration.