Develop a whole new reality,
with Massless for Developers

The Massless Pen is the most intuitive, precise and fun input device for art and design available today. We’d love you to create solutions using the Massless Pen which fire the imagination and inspire minds, hearts and… hands.

Whether you’re developing a drawing app, a training/education app, a modelling app, a new display device or head mounted display, you can easily develop with your favourite game engine or with our native APIs.

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Everything needed to quickly create incredible virtual experiences

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Massless API Documentation

Whether you’re developing a virtual reality game, entertainment or app

API Documentation

Download Pen API

Download the Massless API and start integrating the pen into your app

Download Pen API


Frequently asked questions and minimum system requirements

Read the FAQ

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The Massless API contains everything needed to quickly create incredible experiences inside and outside of VR using the Massless Pen. The Massless Pen has an amazing set of features to use in your User Experience development:

All of this capability is packed into the elegantly designed Pen.

Download the Getting Started with Massless Pen Guide

Six DoF
6 DoF from optical tip tracking and an (incredible) IMU
Vibration Feedback
Haptic vibration feedback using a mini ERM
Detect Distance
The ability to detect distance from a physical surface using surface sensing
Touch Sensor
Touch pad input using a capacitive sensor
Gesture control
using the IMU
VR Compatibilities
Works with
Oculus Rift, HTC Vive, Vive Pro and Valve Index

Massless API Documentation

We provide an API for developers to include input from the Massless Pen in their own applications. This takes the form of a C-API in a native DLL built for 64bit Windows. We also include the corresponding header (.h) and library (.lib) files to conveniently link against this API.

A well-documented guide for the Massless API

Read the API documentation or Download the API itself

Structure of API
The API is simple, containing only a small amount of functions
Coordinate system
Massless API follows the computer vision convention for coordinate systems
Full functions documentation for API
Provide information on how to get started using the API, and what exactly it will output.

Frequently Asked Questions (FAQ)

How does The Massless Pen work?

We use an infrared stereo camera in the Massless tracker to optically track the position and orientation of multiple active marker points on the Pen. We fuse the optical data with the orientation data from the onboard IMU that is transmitted wirelessly to the host computer.

Minimum system requirements in VR?

Any “VR Ready” PC will be compatible. Most VR headset companies provide a “Specification test” on their websites. While this does vary depending on the system used, Massless minimum requirements will easily be met by all of them.

Alongside meeting Massless’ minimum requirements, you will need a spare USB3.0 port (type A) after you have plugged in all the required devices for the headset you are using.

Category Hardware
Processor Intel Core i5-4590

AMD FX 8350

(equivalent or better)

Graphics card NVIDIA GTX 970

AMD Radeon R9 290

(equivalent or better)

RAM 8GB or more
Video output One HDMI 1.4 or one DisplayPort 1.2
USB One available USB-A 3.0
OS Windows 8.1 or newer

Recommended system requirements in VR?

These are the specs that Massless recommends to run the Pen. You can, of course, have better performing hardware than what is listed here.

Category Hardware
Processor Intel Core i5-4590

AMD FX 8350

(equivalent or better)

Graphics card NVIDIA GTX 1060

AMD Radeon RX 480

(equivalent or better)

RAM 8GB or more
Video output HDMI 1.4 or DisplayPort 1.2
USB One available USB-A 3.0
OS Windows 8.1 or newer

Minimum system requirements outside VR?

The Massless Pen can be used inside and outside of VR. A user can alternate between inside and outside of VR and use the same recommended system requirements that the Pen requires within VR, but for users never intending to use the Massless Pen inside VR, any PC compatible with your 2D or 3D application will be suitable. However, regardless of whether are working “inside” or “outside of VR, you will still need a spare USB3.0 port (type A).

What VR systems is the Pen compatible with?

We currently support the HTC Vive, Vive Pro, Vive Pro Eye (and any compatible) and the Oculus Rift CV1. Our API and plugins are being developed to allow for compatibility with future VR systems and software.

We are also ensuring that our physical connectors use industry-standard dimensions where possible, to allow for maximum compatibility with existing/future VR systems.

How accurate is the Pen?

Very accurate! One reason we created the Massless Pen the way we did was for precision design, drafting and drawing. It is very complicated to accurately track a beautiful, slender object like the Massless Pen in 3D space, but it delivers an incredible and intuitive experience for the user. The Pen is extremely accurate in the X and Y directions relative to the Massless tracker. Since we are using a stereo camera setup, the error in the Z direction increases with the square of the Z distance from the Massless Tracker. That means that the further the Pen is from the tracker, the less precise it becomes. Under 300mm from the tracker, the accuracy is sub 1mm. Over 1 meter, the accuracy is between 2 and 3mm.

The tracking volume and accuracy can be increased by adding a second Massless tracker.

In VR, do I need to use an off-hand controller as well as the Pen?

Not necessarily. There are a number of events that are generated by the Pen that can be used as inputs to a software application. These include a capacitive touch sensing pad on the Pen that can be used for button and scroll input, the IMU can be used for twist and flick input and the optical tracking can be used to change the function of the Pen. Depending on the UI of the software that you are using, this may alone be enough. However, certain extended functionality may require the use of an off-hand controller. Massless Studio uses menus on the off-hand controller that are accessed by pressing the virtual buttons using the Pen.

How big is the tracker’s field of view (the Pen's tracking volume)?

The F.O.V. of the tracker is 90deg. wide and 69deg. high. The further away from the tracker that the Pen is, the larger the tracking volume becomes, but the tracking accuracy will eventually go down. After about 1 meter/yard away from the tracker, the tracking volume is quite big and the accuracy is still very high.

Do I have to use the Massless Pen in VR?

No. The Massless Pen can also function as a 3D mouse input device that works on the physical desktop or in space in front of the monitor. Included in the software suite is Massless Mouse, which allows the Pen to control the on-screen cursor. The capacitive touch sensor is used for the mouse clicks and scrolls. The rear half of the touch pad is a left-click, the front half (near the tip) is a right-click.

Can I use two Massless Pens at the same time with a single tracker?

No, not on the same tracker. However, multiple Pens can be used independently in the same room. Each Pen is explicitly paired to one or more trackers.

Can I track the Massless Pen with other trackers than Massless trackers?

With our current implementation, no, but this is very possible. If you’re interested in tracking the Pen with your tracker technology, then it is most likely very possible to do this. The Massless Pen is designed for highly intuitive and precise desk-based design and the Massless tracker is currently best at delivering that performance, but we’d love to hear your ideas!

Can I use Massless trackers at room-scale?

Not really, our high precision tracking system is intended for desk-based use. With that said – you can be standing and you can be up to 1 meter/ 3 feet away from the tracker. This will give you a big enough tracking volume that you can reach as far as you can in any direction (without moving your feet).