## 3 Results and Discussion
### Scientific Mapping
#### 3.2.2 Hardware
However, there was a technical breakthrough in 2016, with the first public release of technologically mature virtual-reality head-mounted displays, such as the HTC Vive and the Oculus Rift [27; 53]; since then, there has been an increase in worldwide research on virtual [28]. Not only academics, but also practitioners agree that the equipment launched in 2016 was a \"very big breakthrough\" for virtual reality applications [29; 30]. Therefore, although the cost of these devices remains relatively expensive and technical limits exist, the price of virtual reality equipment has reduced year on year, technological constraints have decreased and new features have been developed, resulting in the increased use of head-mounted displays. The HTC VIVE was the most commonly reported model in the studies that employed head-mounted displays. Ten of the studies examined used HTC VIVE, well ahead of the second most frequently mentioned model, the Oculus Rift. The authors of [15; 16; 45] stated that they chose HTC Vive because its tracking sensors work reliably and its controllers allow multimodal hand inputs. Furthermore, HTC Vive supports development in the Unity3D game engine, which has become the standard for the development of virtual reality. The HTC VIVE is a virtual reality headset that consists of a head-mounted display, two wireless handheld controllers, and two lighthouse base stations that emit pulsed infrared lasers. It allows the user to move about and interact with a 3D world using motion-tracked handheld controllers. The VIVE system has two 1080 \(\times\) 1200 resolution displays, one for each eye. The headset and controls also have 70 infrared sensors, a gyroscope, and an accelerometer. These sensors, together with the two lighthouses, track the operator's motions with millimetric precision. The operating system is SteamVR, which runs on Microsoft Windows. A USB connection attaches the VIVE system to the computer [63]. Figure 6 is an example of a study in which HTC VIVE head-mounted displays were employed. Three of the studies examined employed immersive rooms and CAVE-like systems. It is worth noting that all three were published in 2017, shortly after the previously mentioned launch of accessible head-mounted display releases in 2016. Prior to the popularity of head-mounted displays, CAVE equipment was the most frequently utilized technology [18]. However, since CAVEs are expensive, have poor immersion, and are not especially portable,  
Figure 6: Power unit based on CAD data visualized in HTC VIVE head-mounted display [16]. they have been increasingly replaced with head-mounted displays. These claims are supported by the authors of [64], who found that in 2022, 28% of industrial presentations used a virtual reality system, whereas just 4% used a CAVE setting. Motion capture devices are also frequently mentioned. Because sensing in single postures while handling a virtual object is currently inadequate, motion capture devices are utilized to supplement the detection of virtual world players and to reduce occlusion problems. Microsoft Kinect and Vicon models were utilized, with Kinect being used in two different studies by the same research group. Cockpits are regularly cited devices in research on automotive applications. During testing, physical structures equipped with steering wheels, benches, and pedals were mixed with virtual reality elements. A cockpit with a head-mounted display device and sensors to detect hand motions was a common combination. In some experiments, vehicles with their original multimedia systems were employed in comparative evaluations of usability testing in real environments. Participants traveled along simulated routes while engaging with the vehicle's interior controls.