Generating sample looks for geometric objects in a visual design language

A major application of visualisation is to the design of structured objects such as buildings, machinery and electronic circuits, as in computer-aided design (CAD) systems. Complex designs are frequently parameterised so that they represent families of objects rather than single artifacts, and building them requires design environments that support both the concrete visualisation and manipulation of components, and the abstract specification of how they are related. CAD systems usually separate these two aspects, providing the abstract programming capability via a textual programming language grafted on to a 3D object editor and solid modeller. A recently proposed design language merges these two activities by embedding representations of solid objects in a visual logic programming language. A practical issue that arises is how to automatically generate a "sample look, a reasonable representation for a parameterised object which can be displayed during execution (assembly) of a design. We present a solution to this problem based on "factoring", which separates the constraints on a solid object from its geometric properties. (C) 2010 Elsevier Ltd. All rights reserved.