Title: A visual business modelling and simulation environment

We describe Builder, a language and environment for interactive specification and simulation of business-oriented models. The Builder language uses an object-oriented declarative approach, combining a visual specification of the model structure (the business entities) with a declarative specification of model behaviour. The Builder environment supports exploratory development of models, with a tight integration between modelling environment and execution environment. This provides a system with a high degree of liveness, which supports either a concrete or abstract approach to model development. Models can be simulated using two different types of constraint solver, with other types of solver under development. A graphical user interface editor allows a GUI layer to be added to a model for entry of model data and display of results, while a notation editor permits customisation of the model notation.