Main characteristics

PTVR is a free and open-source library for creating visual perception experiments in virtual reality using Python (the PTVR Backend is Unity but knowledge in Unity is not necessary).

The PTVR library's ambition is to let you design and implement visual perception experiments in virtual reality using high-level Python script programming. It is intended to help researchers in behavioral sciences leverage the power of virtual reality for their research without the need to learn how virtual reality programming works.

The philosophy of PTVR is thus very close to the approach of PsychoPy (https://www.psychopy.org/) that has been so important and influential since 2007 for Vision Science researchers displaying stimuli on 2D monitors.

Some assets of PTVR

VR experiments can be created rapidly and succinctly by researchers thanks to clearly structured high-level python scripts.
The use of such scripts, along with the transparency of the PTVR open-source code, is one of the necessary components to address the 'reproducibility crisis' in science and foster Open Science.
Researchers can learn PTVR quite quickly thanks to two main resources:
- A rich online documentation provided with many animated figures in 3D to help visualize some 3D subtleties (will be released soon).
- Many "demo" scripts (included in the PTVR library) with didactic 3D and/or interactive features.
The terminology used in the PTVR code is familiar to vision scientist. For instance, researchers can use an intuitive "Perimetric" coordinate system allowing them to easily place their 3D stimuli with eccentricity and half-meridian coordinates.
Intuitive ways of dealing with visual angles in 3D.
Intuitive ways of dealing with the notorious difficulty of rotating 3D objects.
An implementation of "flat screens" to replicate and extend standard experiments made on 2D screens of monitors.
Easy ways of recording experimental results.
Easy Gaze tracking and recording.
Easy Head tracking and recording.
Focus on the implementation of standard and innovative clinical tools for visuo-motor testing and visuo-motor readaptation (notably for low vision).
Great care to create accurately controlled text stimuli in the spirit of the psychophysics of Reading.

Requirements

An HTC Vive Pro Series VR system (headset, hand controllers, ...) (https://www.vive.com/eu/product/#pro%20series)
A Windows computer with HTC Vive already set-up. See HTC Vive setup for help with this.
Python >3.6. We suggest Spyder, a nice integrated development environment (IDE).

Future PTVR versions will support other VR systems.

UPDATE of 23. August 2024
As the HTC vive Pro Eye is discontinued (bad news), we suggest the following solutions that are currently not as good as the HTC vive Pro Eye (because they do not have an integrated eyetracker):

The best solution is the HTC Vive Pro 2.
It is the best solution in the sense that all PTVR demos have been tested (by researchers in our group) with this headset.
Interestingly it has a better spatial and temporal resolution (compared to the HTC Vive Pro Eye) but unfortunately it does not include an eyetracker (although there are independent eyetrackers that can be fit within the headset, but we did not test them).
The absence of an integrated eyetracker is the only notable difference with the HTC Vive Pro Eye. This is why we strongly recommend this solution if you do not need eyetracking.
Another good solution is the Quest 3 and the less recent Quest 2.
Quite a number of PTVR demos have been tested with these 2 headsets. But note that researchers in our group have not systematically tested all demos with these headsets.
Big advantage: cheap.
Inconvenient: NO eyetracker.
The only potential issue is with the handcontrollers as they do not have the same buttons as those of the Vive Pro, but this is a feature that we might be able to add to PTVR with a reasonable delay.
Also note that the Quest Pro does have an integrated eyetracker but we did not test it at all.

Notes

PTVR is built using the Unity game engine (you will however not have to install Unity yourself).

Attributions of images

Image from Notas de prensa, CC BY-SA 2.5, via Wikimedia Commons.