A Geometrical Modeller for HEP

Geometrical modelling generally provides the geometrical description of a special structure and a set of services to "navigate" through its structure. HEP geometrical modellers are designed to handle high complexity detector geometries and they are usually embedded within simulation MC frameworks. The fact that these frameworks greatly depend on their specific geometrical tools makes simulation applications hardly portable to MC's other than the one they were designed for. The ALICE Off-line Project in collaboration with the ROOT team is proposing a multi-purpose geometrical modeller for HEP that is integrated within a virtual MC infrastructure. This tool has been optimised for performance with the geometry setups of several HEP experiments and provides a single representation for the geometry used by different applications such as simulation, reconstruction or event display.