In 2019, the US Military requested $8.8 billion for the training and education of soldiers for operations and maintenance to fund programs such as recruit training, specialized skills training, and flight training. One method to decrease the cost and improve the efficiency of training is to utilize commodity virtual reality (VR) technology. Studies have shown that this technology can be used in a variety of fields to improve training and learning outcomes with cost and performance benefits. Although previous VR environments have been developed to train personnel, these environments are geared towards a single user, include limited input capabilities, and require expensive hardware preventing them from large scale use. Developing VR environments for multiple users with real-world, passive haptic interactions on low-cost commodity devices will broaden the applications of VR training environments for the military.

To investigate this, a framework was developed to explore the capabilities of the HTC Vive in a multi-user training simulation. In various scenarios, trainees may interact with a plethora of virtual objects. While the Vive provides tracked wands for user input, the physical motions needed to grasp and move the controllers rarely represent the actual motions required to interact with a virtual object. To address this, passive haptics were implemented to provide sensory cues. Furthermore, to support a multi-user experience, the physical and virtual environments were synchronized to allow both users access to the same passive haptic cues. This was accomplished by establishing a common frame of reference through a shared tracking system. To evaluate this framework, informal pilot tests were performed on a simulated maintenance operation. Participants reported high levels of immersion through intuitive interactions with their partners. By combining low-cost commodity devices, this framework provides the benefits seen in expensive VR environments to the US Military at a fraction of the cost.