# Portable VR Welding Simulator
## 1 Introduction  
In the construction and manufacturing sectors, there is a continuous demand for skilled welders. As [1] indicates, in 2022 in Europe, a shortage in this occupation was reported by 17 out of 29 European countries, and welders were among the most needed professionals (ranked third). Forecasts regarding demand for welders in Poland in 2024 indicate job vacancies in almost the whole country [2]. Thus, welding remains an important occupation to be covered by the education and training sector. A professional welder has knowledge and skills that enable them to carry out activities in a correct and safe way. These are acquired by a mix of classroom training and hands-on training [3, 4]. [PERSON] and [PERSON] [5] indicate the following training principles for welders' training: (1) students can practice relevant skills; (2) students' performance is assessed; and (3) students obtain feedback during and after training. Due to the nature of welding, the traditional training of welders is time-consuming and expensive [6]. Welding is a process requiring specialist technical equipment, material (metal, natural gas, welding wire, and consumable or non-consumable electrode rods), and energy. Carrying out welding is a precise and difficult skill, the mastering of which requires complex theoretical knowledge and many practical exercises (hands-on learning) under the guidance and supervision of a trainer who demonstrates, instructs, observes, and provides feedback and verifies the correctness of a trainee's actions and the created weld. Practical demonstrations made by the trainer and welding exercises repeated by the trainee until they can consistently create high-quality welds contribute to the training costs because the joined (welded) elements become waste, and for each trainee, a trainer's working hours must be spent. The safety of trainees also has to be secured. Welders face a number of risks while working, e.g., skin burns, eye damage, hearing loss, inhaling toxic welding fumes and gasses, and electrocution, and thus they have to wear the appropriate personalprotective equipment [7; 8; 9; 10]. Additionally, for practical training, a specialized space or workshop, with all the necessary equipment and infrastructure, has to be prepared. During training, a welder has to learn to move the welding torch in the correct way in terms of speed, position (angles towards the joined elements and the weld being created), path, and distance and, at the same time, observe (\"read\") the welding pool [5; 11; 12]. The continuous evaluation of the correctness of these parameters is difficult, especially for beginners. This ability comes with practice. The trainer can either observe a trainee's posture or the weld being created by them. When the trainer wants to observe the creation of a weld by a trainee, they have to wear a helmet, which makes it impossible to observe the trainee's posture at the same time. All of these conditions contribute to the time spent on practical training by a trainer and a trainee [13]. For years, the development of ICT (information and communications technology) has offered varied opportunities to support welders' training, which has resulted, among other things, in the development of simulators based on VR (virtual reality) [4; 14; 15; 16; 17; 18; 19]. In [PERSON]'s PhD thesis, a literature review covers the attempts and achievements in the development of ICT-based solutions for welders' training, starting with patents of welding simulators registered in the 1970s [19]. Examples of pioneering works in the development of simulators for welders' training are also presented in [20; 21]. VR is considered useful for the delivery of practical training as it enables us to reduce or overcome the problems encountered when carrying out training in a traditional way, which also regards training in welding [5; 13; 22; 23; 24; 25; 26; 27; 28; 29]. [PERSON] et al. [30] raise that in the case of difficult welding tasks, training with the use of a VR welding simulator has to be supplemented with real-world training.