## 5 Discussion  
### Main Findings  
In terms of emotional response, VR free-form modeling led to higher levels of emotional valence and emotional arousal than those of conventional parametric CAD modeling. According to the interviews, the incorporation of VR provided the participants with a sense of novelty and an increased level of operational freedom, which stimulated more positive and intense emotions in them. However, as previously mentioned, we noticed that the significant difference in emotional valence was only 0.04, with the \(p\)-value nearing the threshold. This calls into question whether other research methods might offer more compelling evidence. For instance, other scholars have reported state-of-the-art related studies. Some have confirmed that virtual embodiment intensified the emotional response to virtual stimuli [36]. If we view the operation of CAD as an extension of the individual, we find results consistent with this study, affirming that VR can indeed enhance emotional responses. Furthermore, the literature suggests alternative measurement methods. For instance, electrodermal activity (EDA) has been used to measure physiological responses of users to VR [37], which could be cross-verified with the SAM scale used in this study. These diverse studies can serve as references for future research expanding on emotional responses. On the basis of the results of flow experience, we speculated that the participants had a sense of presence when using the VR product and felt fun and experienced playfulness during their timely interaction with the surroundings in the digital world. In addition, the participants mentioned that, when executing Gravity Sketch 3D, they felt that they had entered another time and space. The VR-based learning model implemented in this study was different from the learning model that the participants were used to; therefore, they experienced increased exuberance when performing VR free-form modeling. Regarding other indices of flow experience, no significant differences were observed in concentration, sense of time distortion, and control between the two techniques. This result suggested that VR did not lead to a higher sense of time distortion, concentration level, and sense of control during operations. The existing literature on flow experience largely pertains to gaming or educational research [38, 39], and a common conclusion drawn from these studies has been that the use of VR could evoke a higher degree of immersion. However, the findings of this study diverge from such conclusions. It appears that once the initial novelty and enjoyment brought by VR are set aside, VR does not live up to its expectations when transitioning into practical work scenarios. In the interviews, the participants who used parametric CAD modeling implied that they lost their sense of direction and space when modeling a precise 3D graphic on a 2D screen; thus, they felt frustrated. Moreover, because the participants had little intuitive interaction with the models, they experienced a relatively low level of fun; therefore, they exhibited low scores in the fun dimension. In accordance with the results of the operational performance, we speculated that the participants obtained more benefits when using VR free-form modeling than when using parametric CAD modeling because VR free-form modeling provided higher intuitiveness. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**Operational Performance**} & \multirow{2}{*}{**Mean**} & \multicolumn{2}{c}{**Standard Deviation**} & \multicolumn{2}{c}{**t-Test on the Mean**} \\ \cline{3-6} \cline{5-6}  & Free-form VR & 8.73 & 9.21 & \multirow{2}{*}{\(-\)2.88} & \multirow{2}{*}{0.006 *} \\ \cline{2-6} \cline{5-6 In an unfamiliar environment, the participants could still determine the correct approach for conducting VR free-form modeling; therefore, they exhibited higher operational performance in VR free-form modeling than in parametric CAD modeling.