Innovative load-bearing designs depend on a careful balance between creative shape and structural performance. While existing preference-based topology optimization methods let designers add subjective preference, they pose high design experience barriers and suffer from inefficient interactions due to reliance on skilled manual sketching. In this study, we propose the bidirectional evolutionary structural optimization with skeleton control (SC-BESO) method. This method begins with extracting the skeleton graph of an existing design, where users can subjectively drag its skeletal nodes to deform the design. The deformed design is then used to guide the generation of its optimized structural design. A design parameter allows users to adjust the optimized result toward either performance-driven or preference-driven outcomes. Based on the proposed method, a cross-platform digital design tool, TouchBESO, is developed for 2D structural designs. Parametric studies show that, even after user interaction that results in stiffness reduction, the SC-BESO method can regain most of the lost performance with only small shape changes. Furthermore, a 3D cantilever example illustrates the scalability of the method, and two potential integrations with drawing systems and the similarity constraint are discussed for future interactive design frameworks.

Innovative load-bearing structures often emerge from a fine balance between creative forms and engineering principles. While preference-based topology optimization methods have advanced structural design by considering designers’ geometric preferences, they struggle with visualizing and editing complex 3D details crucial for diverse design options. To overcome this bottleneck, here we propose the improved bidirectional evolutionary structural optimization considering subjective preferences (ISP-BESO) method. This method introduces a similarity constraint that enables precise control over subjective preferences in optimized structures. Then, a design exploration strategy is proposed by integrating virtual reality (VR) with topology optimization for the interactive creation of desirable 3D structures. The strategy employs VR sculpting to offer immersive visualization and real-time feedback, guiding material redistribution during optimization. This workflow can iteratively produce innovative and efficient structures. Adjusting target similarity in ISP-BESO steers designs toward performance-driven or preference-driven outcomes. A museum design example demonstrates the practical potential of this strategy. • A novel preference-based topology optimization method is proposed. • The proposed method can control the influence of preferences on optimized structures. • A design exploration strategy is proposed by combining VR with topology optimization. • The strategy can iteratively perform sculpting and optimization to design structures. • A VR-based digital design tool integrating the proposed strategy is developed.