<p>This study explored the crucial role of the ideation phase in product development, focusing on how different sketching tools—hand sketching and virtual reality (VR) sketching—affect designers’ creative thinking. The comparative analysis of these two tools highlighted the importance of understanding how each of them influences cognitive processes and outcomes during idea development, offering valuable insights for design education and practice. Combining theoretical review and experiments in which participants used both hand and VR sketching to generate and refine ideas, the study applied protocol analysis to identify and analyze the actions taken during sketching processes, including the frequency of and transitions between these actions. This analysis indicated that while designers utilize VR sketching and hand sketching similarly in core cognitive processes within design education, their physical interactions and conceptual focus with the two tools differ significantly; this suggests that strategic integration of the two tools may be necessary to foster diverse thinking patterns. While hand sketching yielded consistent results that reflected personal style and creativity, VR sketching results varied to a greater extent based on external factors. This finding highlights the unique potential of both tools for individual characteristics- and performance-based design education. The study’s analysis of action frequency, sequence, movement, and design results revealed that hand sketching facilitates the development of diverse concepts based on existing knowledge, while VR sketching encourages in-depth engagement with specific aspects of given designs, indicating that these tools have distinct educational benefits for different stages and facets of the design process. These findings suggest that the appropriate use of both hand sketching, which promotes broad idea generation and conceptual transformation, and VR sketching, which supports detailed exploration and structural/conceptual modifications, constitutes a comprehensive educational approach that can enhance product design students’ creative and critical thinking skills. In conclusion, this study sheds light on the unique roles performed by VR sketching and hand sketching in the idea generation phase of product design. Indeed, it provides important foundational data for effective tool selection and integration in the evolving landscape of design education. Nevertheless, the generalizability of its findings may be limited, and follow-up studies should seek to address this limitation. </p>