Design Intent for CAD model assemblies

An assembly is where the sub-assemblies and partswhich comprise a productcome together. The intellectual arrangement of parts in an assembly is a difficult task.ModernCAD environments containtools which allow CAD part models to be brought together and problems such as clashes to be discovered. If these problems are not solved before manufacturethe physical parts will not assemble together without expensive rework. This paper introduces a conceptual framework to model assemblies in CAD by enforcing design intent. The definition of design intent is extended to include more than just the geometric description of the part models and shapes. An automated approach is proposed which identifies the parametric relationships between parametersin different parts in an assembly. Sensitivities are calculated for each parameter defining the assembly, which are then used to: (a) identify parametric relationships between different parameters in the CAD assembly, and (b) constrain the assembly using the identified relationships to define the design intent of the assembly. A well-captured design intentfor assembly modelswill enable the designer to design out manufacturing and assembly difficulties at an early design stage. The approach has been tested on a number of example models in this paper.