The increasing development of three-dimensional virtual city models and leading-edge computer software applications is providing innovative possibilities for analysing the performance of existing city centre public squares. In the design and assessment of city squares, the use of accurate virtual city models is often limited to visual geometrical assessment only. There is little evidence that such models are being adapted to carry out urban performance simulations. There is however existing and emerging tools that can simulate a number of performance aspects– pedestrian movement, noise level, wind movement and temperature, that show scope for integrating virtual city models to aid in the assessment of public squares. This paper describes a study which investigates the interoperability of “off the shelf” three-dimension al virtual city models to integrate with selected “urban performance” software to contribute to a more integrated approach to the assessment of existing public squares and the future sustainability of virtual city models. Methodologies for utilising virtual city models within “urban performance” software are established, with results demonstrating that the integration of virtual city model data can aid in both the visual and performance assessment of existing public squares, with scope for application to new proposals. The argument is also made that the application of virtual city models in this manner also contributes towards the sustainability of virtual city models, one that takes a more multifunctional approach. This paper acknowledges that the majority of the evaluated software is not related directly to urban design – indeed there is no software currently available that brings together all the performance aspects and relates them to geometrical characteristics. However this study offers a significant contribution to this subject and identifies the need for future research into the evolution of information rich virtual city models.