Multi-user Networked Interactive Augmented Reality Card Game Marissa D´ ıaz, Mois´ es Alencastre-Miranda, Lourdes Mu˜ noz-G´ omez, Isaac Rudomin Tecnol´ ogico de Monterrey - Campus Estado de M´ exico (ITESM-CEM) Virtual Environments and Robotics Laboratory (VERLAB) Carretera Lago de Guadalupe Km. 3, Atizapan de Zaragoza, 52926, Estado de M´ exico, M´ exico dmarissa@itesm.mx, malencastre@itesm.mx, lmunoz@itesm.mx, rudomin@itesm.mx Abstract Many efforts to improve interaction in virtual and aug- mented reality applications do so by including tactile ele- ments to create a link between virtual objects and actions. It is also important to add collaboration, expanding single user interaction to networked user to user interaction. In this paper, we describe a networked virtual card game for multiple users based on a collaborative virtual environ- ment. This game is a networked augmented reality game that uses an inexpensive tangible card flipping device allow- ing the system to be used in homes,museums, schools. The game is easy to set up and capable of hosting several re- mote users in a distributed system. We constructed two card flipping devices so we can show complete experimental re- sults with two computers and their corresponding hardware interfaces. 1. Introduction Collaborative games that use tangible interfaces as Hu- man Computer Interfaces (HCI) with objects enhanced by computation, try to link and create a separate virtual envi- ronment for the users in order to expand the user’s capabil- ities through internet communication. Interaction [10] must be made clear by using self ex- planatory components and must create the illusion that the place where actions are taken is the virtual world. Aug- mented reality (AR) collaborative games like [7, 6] that place the user in an augmented world empower the players to believe and to enjoy the joint experience freely. The suc- cess of a game that has interaction between users depends in great measure, on the communication’s system speed, ro- bustness and the correct replication of events for each player in the game. There is already a number of people working in collab- orative AR systems [3, 4, 11, 8]. The main idea in this kind of systems is to allow multiple users to interact with the same augmented environment. Collaborative AR systems are also used for different games [4, 11, 8] like virtual hockey, virtual tennis and ”Concentration”. However most work mentioned in the previous para- graphs, use face to face collaboration. This means that users interact in the same physical environment in the same loca- tion, so it is not remote collaboration. On the other hand, there are several Networked Virtual Environments (NetVEs) or Collaborative Virtual Environ- ments (CVEs) that allow multiple users to collaborate, in- teract and communicate in a common Virtual Environment (VE) regardless of the geographical locations of the users [5, 12]. In [2] live video is integrated into a NetVE system (called VLNET), so the participants are sharing a mixed en- vironment with real and virtual objects in a teaching appli- cation. In this paper, we propose a networked augmented reality game with cards. The application was developed based on a distributed, multiplatform and modular CVE with the ca- pability of mixing real video with the virtual environment. Each user interacts physically with its own tangible HCI and interacts virtually through the CVE with other remote users, all feeling as if they are playing the card game in the same location. 2. Multi user augmented card game People around the world have each day less time to in- teract physically with other people; multi user games try to provide a safe environment to interact with others. “Memory” is a commonly played card game that can be played alone or with many people at the time. It is simple but enjoyable, and also works as a brain exercise. As in other virtually enhanced games [6, 13], we wanted to create a vast playground that serves as a place to detach from each day activities, but we wanted to take a different