Defining behaviours for solids in a visual design environment

The design of structured objects is frequently accomplished with the use of CAD systems, some of which allow for parametrised designs, which represent families of objects. Some existing CAD systems permit parametrisation by providing interfaces to programming languages, leading to a sharp division between the visual and programming aspects of building complex designs. In previous work, a design language LSD was proposed, which used visual logic programming to overcome this separation and provides "assembly semantics" for building an instance of a parametrised design corresponding to specific parameter values. Also of interest to designers, however, is the behaviour of the objects they design. For example, the point of building a mechanical device such as an internal combustion engine is to obtain a particular mechanical behaviour. Here we extend the formal model for solid objects on which LSD relies in order to support the definition of particular kinds of behaviours.