Current software visualisation tools do not address the full range of software comprehension requirements. This paper proposes a novel software visualisation model for supporting object-oriented software comprehension that is intended to address the shortcomings of existing tools. We discuss the previous work that prompted us to develop this model. An initial model is then presented, based on multiple levels of abstraction, multiple perspectives of the software system, and the integration of statically and dynamically extracted information. We review the evaluation tasks used in our previous work and those from the software visualisation and comprehension literature to produce a refined set of evaluation tasks. We then use these tasks to perform an initial assessment of the proposed model. The refined model is then defined more formally. Finally, a concrete example of the use of the model to generate abstraction hierarchies is discussed. We conclude that a visualisation model incorporating a hierarchy of interrelated abstraction levels, combined with structural and behavioural perspectives of the software, will provide effective support for software comprehension.