Building assembly detailing using constraint-based modeling

Constraint-based geometric modeling entails specifying geometric constraints to control the locations of the components in an assembly. Consequently, any future modifications of the components are governed by these constraints. In this paper, a set of constraint-based assembly operations for generating 3D details of building assemblies are presented. The operations constrain the locations and orientations of the components in a building assembly through a series of constructive steps and therefore allow for easier modification. These operations are used in a modeling system that extends the idea of constraint-based modeling to detailing architectural building assemblies. The system utilizes the constraint-based assembly operations, which employ traditional geometric constraints integrated with a set of constructive assembly operations. The constraint-based assembly operations allow for a more systematic generation of the assembly details, which can save repetitive work and reduce mistakes resulting from copying and pasting old details. Also, the technique allows the assemblies to be studied and analyzed. To illustrate this idea, a prototype 3D constraint-based system for assembling three-dimensional architectural details was developed. With the proposed system, the details of building assemblies do not need to be reinvented for every project. Examples of the proposed approach are provided and its limitations and benefits are discussed.