SubtleGame
SubtleGame is a single-player iMD-XR game developed using the NanoVer iMD-VR framework and is publicly available on GitHub. SubtleGame is designed to run psychophysics experiments for quantifying the threshold at which players can sense differences in the properties of molecular simulations when interacting with them in VR.
Design of SubtleGame
SubtleGame facilitates three mini games:
Psychophysics trials: distinguishing between buckminsterfullerene molecules of different rigidities with a two-alternative force-choice (2AFC) psychophysics design
Nanotube task: threading a methane through a carbon nanotube
Knot-tying task: tying a knot in a 17-alanine polypeptide
Players are also able to take part in a practice simulation at the beginning of the game to familiarise themselves with how to interact with molecules. In this simulations, players interact with two hydrocarbons with either their hands or controllers.
Read on to find out more about the purpose of each mini-game…
The Psychophysics trials
This mini-game employs a two-alternative forced-choice psychophysics experimental design, during which players take part in several trials.
In a single trial,
The player is given two buckminsterfullerene molecules to interact with for 30 seconds.
After the time is up, they must select the softest, i.e. the one that is the least rigid and deforms the most easily. The player does this by placing their hand/controller inside their chosen molecule. They must make a choice even if they are unsure!
The rigidity of the molecules is changed by scaling the angle force constants of all of the bonds in the buckminsterfullerenes. The rigidity of the two molecules presented in each trial is randomly selected from the available simulations. The player is told whether they are correct after each trial and is given their total score across all the sets of molecules at the end of the mini game.
Technical implementation
The nanotube & knot-tying tasks
The nanotube and knot-tying tasks serve several purposes:
To provide training to the player in interacting with the simulations in a gamified setting, encouraging players to lean into their competitive spirit!
To analyse players’ abilities to perform molecular manipulations, such as: calculating the total work done on the molecule as a metric for the ‘goodness’ of a trajectory, and investigating the distribution of completion times across participants as a metric for how difficult the participants found the task
To produce molecular trajectories for training AI models to perform molecular manipulation tasks in iMD-VR.
SubtleGame comprises of two parts:
A VR client written in Unity
A python game manager consisting of a set of python scripts that handle the behind-the-scenes game logic
These components communicate via a NanoVer server, which runs the interactive molecular dynamics simulation.
The custom VR client is a Unity3D project that handles: the VR logic (via the MetaXR SDKs), the user interfaces, and communicates the state of the player to the python game manager (via the server).
The python game manager is a set of python scripts that handles the game logic, e.g. switching simulations, setting molecular visualisations, and on-the-fly calculations for monitoring task progression.
The SubtleGame README provides instructions for running the game.
Publications
R. Roebuck Williams, J. Barnoud, L. Toledo, T. Holzapfel, D. R. Glowacki, Measuring the Limit of Perception of Bond Stiffness of Interactive Molecules in VR via a Gamified Psychophysics Experiment. In: De Paolis LT, Arpaia P, Sacco M, editors. Extended Reality. XR Salento 2024. Lecture Notes in Computer Science, vol 15027. Cham: Springer; 2024. https://doi.org/10.1007/978-3-031-71707-9_13 (also see arXiv:2409.07836)