# A Scoping Review on Virtual Reality-Based Industrial Training
## 1 Introduction  
Staff training is a continuous process that must be focused on the needs of each company, and it is also vital for the proper development of institutions. At the industrial level, the same thing happens, the correct training of workers helps to achieve the strategic objectives and to establish its productive value. However, despite being so necessary, continuous training is undervalued by top management, generating outdated human resources, and, therefore, low-quality products/services [1; 2; 3].  
In many cases, learning during job performance affects the stability of processes. For this reason, it must be decided whether the learning and training of personnel should be carried out during the actual operation, with possible loss of time; or, in a previous phase without compromising the efficiency of the process [4; 5]. Learning opportunities in the value chain are limited due to the variability of its environment, i.e., it is complex to implement changes during production execution. At this point, putting the quality, safety, and efficiency of the production line and workers at risk is unacceptable [6].  
To solve these problems, in recent years, industry 4.0 has arisen, whose objective is to improve processes and increase the productivity of industries. Among the technologies that have been used to fulfill this purpose, the industrial internet of things (IIoT), intelligence and artificial vision, virtual reality (VR), and augmented reality (AR) can be mentioned [7].  
VR, which is the aim of this study, can be defined as a virtual recreation of the real world. Its objective is to transport the user to fully digitized and interactive environments. This technology was originally conceived for video games; however, it has reached various fields, such as industry, medicine, army, education, and tourism [8].  
VR has allowed for the creation of simulation environments for real processes and situations. Furthermore, it has proven to be an adequate way to reduce training times, prevent errors, or even improve the quality of products [9]. The motivation to implement this technology arises from the fact that it is presented as a low-cost alternative when it comes to training and preparation for the use of specialized equipment. VR offers the user an immersive, interactive, and innovative learning process, in contrast to traditional teaching, whose monotony generates rejection and boredom [10; 11]  
Unity 3D is one of the most used software to develop VR, a graphic engine that, together with head-mounted displays (HMD), provides an intuitive and friendly programming environment, in addition to allowing a high degree of immersion for its users [9; 12; 13; 14; 15].  
Several aspects can be studied regardign industrial training based on VR, such as characteristics, devices, approaches, specific applications, among others, as described in previous paragraphs. As a result, this article develops a scoping review in order to better understand the use of this type of technology in industrial training because it is one of the key-technologies where VR will be useful within five years according to the Digital Twin Consortium [16].  
This article has five Sections, including the introduction and it is structured, as follows: Section 2 presents the methodology followed to select the VR articles, Section 3 itemizes the literature review and obtained results, Section 4 shows the benefits, predictions, and possible future uses of VR, and finally, Section 5 details the conclusions.