This study examined the strengths and weaknesses of Gravity Sketch, which is a virtual-reality (VR) sketching and modeling tool, in the later stages of personal sketch creation. Seven designers with at least 4 months of experience with this tool were invited to sketch out ideas in VR and on paper, and their sketches were examined through qualitative analysis based on retrospection interviews and grounded theory. The results of this study highlight the strengths and weaknesses of VR sketching in product design; clarify designers’ timing of switching between paper and VR sketching; and confirm the inference of our previous study that VR sketching is suitable for designers to verify, modify, and explore shapes intuitively in a three-dimensional (3D) space after they have generated a preliminary design idea. In contrast to paper sketches, VR sketches are created in an environment with highly precise visual information, and VR sketching involves additional creation steps compared with paper sketching, thereby reducing the speed and abstractness of sketching. These characteristics of VR sketching prompt designers to focus more on modeling instead of sketching when using VR tools. In contrast to regular 3D modeling software, VR sketching tools do not limit the ability of designers to create shapes and sketch out ideas, even when they are more proficient in creating paper sketches and lack experience with VR modeling.