Interactive truss design using Particle Swarm Optimization and NURBS curves

This paper presents an interactive framework for the design of truss structures with incorporation of the subjective influence of user feedback in the design process. In the devised framework, the truss chords are described using Non-Uniform Rational Basis Splines (NURBS), a representation typically used in computer aided design (CAD) for describing free-form geometry. This allows for a convenient interface between the optimization scheme, namely a particle swarm optimizer (PSO), and the user. Based on the assumption that aesthetic design goals are not straightforwardly quantifiable, key elements for an interactive optimization framework are derived, and implemented for the design of truss structures subject to an additional set of structural criteria/constraints. Setting off from an initial design the user can visually assess interesting solutions that arise during the optimization process, save them for later assessment, actively drive the optimization towards individual goals, re-initialize the process from a set of preferred solutions, or restart the design. For translating the user's perception into quantifiable terms, a criterion is introduced to measure the similarity of candidate solutions with respect to reference designs. The framework is then applied in the design of 2D and 3D truss structures. The effectiveness of the similarity criteria, as well as the ability of the user to drive the optimization towards specific design goals is demonstrated.