MOFA

Overview

As the prevalence of Mixed Reality (MR) head-mounted displays (HMDs) grows, the context of collocated MR gaming is evolving from private, controlled environments to spontaneous, public settings, echoing speculative fiction scenarios. Everyday locales are thus transformed into potential gaming stages, blurring the line between designated play areas and the public realm. This evolution prompts the need for game designs that cater to all present individuals, including HMD players ("Wizards") and non-HMD bystanders ("Muggles"). Addressing this scantily researched field, we developed the Multiplayer Omnipresent Fighting Arena (MOFA) framework, utilizing device asymmetry and role diversification as affordance to actively engage every participant. MOFA explores this approach through a family of prototypes: The Training, The Duel, The Duck, The Dragon, and The Ghost. Each tests how different roles and devices can give people a place in a shared game.

MOFA was honored as the "Best Interactivity Demo" at CHI 2023 and "Best In The Show" at SIGGRAPH 2024.

Playing together in the same place

MOFA treats a street, room, or gathering as a potential arena. A headset wearer and a person holding a phone can occupy different roles in the same game. This device asymmetry is central to the design: participation does not depend on everyone wearing identical equipment.

The prototypes explore magical training, duels, and encounters with shared creatures. The Ghost develops the approach into an asymmetric social exertion game, documented in the CHI PLAY 2024 demonstration. Across these works, bodily movement and the responses of nearby people give virtual actions their social setting.

Making a shared arena

The system uses local Bluetooth and Wi-Fi networking and a coordinate-registration method based on QR codes. Nearby devices share the positions and timing needed to place their virtual content in the same physical space. This work led to InstantCopresence, published at ISMAR 2023 and released as a Unity package. Development account and SIGGRAPH Best in Show award.

Publications

• 2025 — Towards Immersive Mixed Reality Street Play: Understanding Co-located Bodily Play with See-through Head-Mounted Displays in Public Spaces. Proceedings of the ACM on Human-Computer Interaction (CSCW). Full Paper. [→]

Demonstrations

• 2024 — MOFA The Ghost: Demonstrating an Asymmetrical Social Exertion Game in Spontaneous Collocated Mixed Reality. Companion Proceedings of the Annual Symposium on Computer-Human Interaction in Play (CHI PLAY Companion ’24). Tampere, Finland. Interactivity. [→]
• 2024 — MOFA: Multiplayer Omnipresent Fighting Arena. Proceedings of the 2024 Conference and Exhibition on Computer Graphics and Interactive Techniques (SIGGRAPH ’24). Denver, USA. Immersive Pavilion. 🏆 Best in Show. [→]
• 2023 — InstantCopresence: A Spatial Anchor Sharing Methodology for Co-Located Multiplayer Handheld and Headworn AR. 2023 IEEE International Symposium on Mixed and Augmented Reality Adjunct (ISMAR-Adjunct ’23). Sydney, Australia. Demo. 🏆 Honorable Mention. [→]
• 2023 — MOFA: Exploring Asymmetric Mixed Reality Design Strategy for Co-located Multiplayer Between Handheld and Head-mounted Augmented Reality. Extended Abstracts of the 2023 CHI Conference on Human Factors in Computing Systems (CHI EA ’23). Hamburg, Germany. Interactivity. 🏆 Best Interactivity Demo. [→]

Exhibitions

CHI Play 2024 Interactivity. "MOFA the Ghost". Tampere, Finland.

SIGGRAPH 2024 Immersive Pavilion. "MOFA". Denver, U.S.A..

ISMAR 2023 Demonstrations. "InstantCopresence". Sydney, Australia.

CHI 2023 Interactivity. "MOFA". Hamburg, Germany.

Media and Talks

SIGGRAPH Blog: Immersive Experiences for All Environments [→]

@article{Hu_2025,
  title={Towards Immersive Mixed Reality Street Play: Understanding Co-located Bodily Play with See-through Head-Mounted Displays in Public Spaces},
  volume={9},
  ISSN={2573-0142},
  url={http://dx.doi.org/10.1145/3757679},
  DOI={10.1145/3757679},
  number={7},
  journal={Proceedings of the ACM on Human-Computer Interaction},
  publisher={Association for Computing Machinery (ACM)},
  author={Hu, Botao Amber and Lin, Rem RunGu and Tao, Yilan Elan and Laato, Samuli and Li, Yue},
  year={2025},
  month=Oct,
  pages={1–46}
}