## 3 Results and Discussion
### Scientific Mapping
#### 3.2.9. Lack of Realism as a Result of Unnatural Tactile and Visual Senses  
The difficulties of non-natural interactions between individuals and virtual prototypes owing to visual and tactile constraints were addressed frequently in the research reviewed. The complicated interactions in virtual reality have proven to be major drawbacks in industrial settings [50]. The authors of [15] reported that haptic feedback and multimodal interactions are still problematic and concluded that there is a lack of visualization and interaction techniques that fully harness virtual reality's potential. The authors of [48] found that the movement of participants' hands could not be well simulated, and that positioning offset occurred frequently, while [41] identified that interacting with the geometry using the Wii Remote game control was too awkward and unnatural to fully investigate participants' assembly inquiries. The authors of [41] found that the collision detection experience was insufficiently robust to be helpful in their study. Several users reported issues with virtual object feedback when compared to external device motions, such as steering-wheel twisting. Another issue mentioned was that the sense of reach and the dimensions of virtual items do not correspond to physical interaction features, such as buttons or flat surfaces that mimic multimedia screens [46; 52]. Given the significance of natural human connection with a virtual interface, haptic devices such as gloves, suits, and others may strengthen the sensation of immersion. Including haptic technology to allow human interaction modeling of natural human senses and motion would result in a significant improvement in usability testing. In [48], for example, it is suggested that replacing the handle with data gloves could simulate hand movement. As a result, the effectiveness of incorporating haptic devices to improve usability testing is connected to the purpose of the testing, the complexity of the interaction, and the maturity of the virtual item under consideration. Haptic devices should be avoided for usability testing on products that are still in the early stages of development and do not have accurate hand-and-finger interaction. The lack of realism is caused not just by touch sense issues, but also by visual sense issues. In [46], it was observed that readability and representation in a virtual prototype system were troublesome, which the authors attributed to the head-mounted display's low display resolution. Some participants in the tests conducted in [46] complained that they could not view the virtual environment clearly. The study discovered that the image in the virtual environment is not fine enough, and that it is limited by the hardware devices, requiring more dynamic movement behavior and improved graphics resolution from the virtual prototype. Due to complex interaction systems or surroundings with a substantial amount of visual information, high graphical representativeness is essential. Otherwise, only systemswith a limited number of interactions may effectively correlate with conventional usability testing [67]. A major issue is that employing virtual-reality technology without an auxiliary device, such as hand-tracking sensors, may influence user perceptions and, as a result, test findings. The adoption of a physical property, such as a flat wood table emulating the screen of a multimedia system, is one strategy for providing tactile feedback to a user engaged in a virtual environment [66]. Each participant's perception of a product's depth, reach, and dimensions is spontaneous and instinctual during usability testing with physical prototypes. However, in virtual reality, the user desires touch with certain physical devices in order to handle objects in the virtual world; thus, visual calibration and positioning algorithms are necessary to modify the environment and virtual objects in order to provide an accurate user experience.