ALICE, the experiment dedicated to the study of heavy ion collisions at the
LHC, uses an object-oriented framework for simulation, reconstruction and
analysis (AliRoot) based on ROOT. Here, we describe the general ALICE
simulation strategy and those components of the framework related to
simulation. Two main requirements have driven the development of the simulation
components. First, the possibility to run different transport codes with the
same user code for geometry and detector response has led to the development of
the Virtual Monte Carlo concept. Second, simulation has to provide tools to
efficiently study events ranging from low-multiplicity pp collisions to Pb-Pb
collisions with up to 80000 primary particles per event. This has led to the
development of a variety of collaborating generator classes and specific
classes for event merging.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 6 pages, LaTeX, 5 eps figures. PSN
TUMT00