The research paradigm is the foundation for the construction of the design research model. This study starts from the research paradigm to construct a design research model: the Research Tree Diagram. The crown part of the model presents the different levels of design research from five aspects: ontology, epistemology, methodology, approaches to theory development, research strategies, and data sample ethics. The root of the model shows the influence sources of design studies as an interdisciplinary field. As an information visualization tool, the Research Tree Diagram graphically delineates the multifaceted nature of design research, enabling researchers to systematically comprehend its intrinsic logic and interconnections. For novice researchers, it serves as a pedagogical scaffold to rapidly grasp design research methodologies. The model’s efficacy is validated through a case study that demonstrate its practical application in structuring and executing design research projects. This example illustrates how the diagram facilitates the alignment of theoretical frameworks with empirical practices, ensuring methodological coherence.

This study focuses on additive manufacturing (AM) to remodel an ergonomically optimized Leiqin leg rest. To address the design deficiencies of traditional leg rests regarding playing comfort and stability, iterative optimization techniques were employed alongside the Theory of Inventive Problem Solving (TRIZ). Photosensitive resin material was chosen, and a parametric modeling approach was utilized to accurately construct the leg rest model, resulting in the successful development of a double-layer rotating arc-shaped leg rest. Systematic acoustic testing and semi-structured interviews with ten Leiqin players were subsequently conducted for evaluation. The results indicated that the redesigned leg rest significantly outperformed traditional designs in terms of both comfort and stability. This study not only validates the application value of additive manufacturing in enhancing traditional musical instruments but also offers a new technological paradigm for the ergonomic design of musical instrument accessories.