The “Botafumeiro” VR: Virtual Reality in the Liturgy of the Middle Ages

Santiago de Compostela, a city in Galicia, in the northwest of Spain, has been a famous Christian pilgrimage site since the Middle Ages. One distinctive element of the liturgy of the Cathedral of Santiago de Compostela is the use of a giant censer “O Botafumeiro.” It is tied to a rope that hangs from the center of the transept of the arms of the cathedral, and it is pulled through the transept of the cathedral, basically describing a pendulum movement. A team of men called “Os Tiraboleiros” pulls the supporting rope in a pumping cycle to increase the energy of the system, and therefore the angle of oscillation. This pumping process transforms the pendulum motion into a variable-length pendulum motion. We present the specific case of the virtual simulation of the liturgy of the Botafumeiro by VR techniques. The simulation allows users to play the role of the Tiraboleiros as a part of this old tradition. We present the system architecture, the design of the visualization system, a special user interface that simulates the pull of the Botafumeiro, and the experiences of its use with different users of the system.