## 3 Materials and Methods
### Industrial Context: Maintenance Method and Technical Documentation Creation  
KONE is a large manufacturing company, producing elevators, escalators, and automatic building doors. In addition, KONE provides maintenance services, which is an essential part of the revenue. Design for maintainability is an important area of product innovation, and maintenance methods are developed, and corresponding documentation created, as a part of the product development process. The maintenance instructions on how to perform maintenance tasks are used both in field work and in training [60].  
Maintenance methods and the related technical documentation are developed iteratively in close cooperation with the maintenance development department (MDD) and the technical documentation department (TDD). The departments consist of multinational multidisciplinary teams, located in different locations and time zones. The major challenges of such collaboration include the lack of access to real equipment and the limitations of traditional channels (e.g., Teams, emails) to communicate complex product information, such as geometry and assembly/disassembly procedures.  
Figure 2 shows the current pipeline of maintenance method development and technical documentation creation. Method developers create and design maintenance methods, which are further written and illustrated by technical writers and illustrators from TDD. Due to the frequent unavailability of physical equipment or prototypes, the method developers might never interact with real equipment and perform their tasks based on 2D images or 3D models on a computer screen. Such an approach is error-prone due to the limited spatial and contextual understanding and might lead to a situation where the method cannot be performed in reality, or requires unexpected additional work. Maintenance method developers use markups in existing pdf files or paper copies to create an outline: a draft version of the maintenance method. Once the outline is ready, technical writers and illustrators develop it further into technical instructions. If the writers and illustrators have no access to the equipment, they rely solely on the outline and notes given by the maintenance method developer. In many cases, this results in misinterpretations and mistakes. When a draft is available, it is reviewed and commented on by the method developer, and the comments are then implemented into the draft by the technical writer and illustrator. The commenting might take several rounds until both parties are happy with the draft. The number of rounds is increased by any misunderstandings or communication problems, especially if the parties involved are not physically in the same location.  
Figure 2: The process of maintenance method development and documentation creation at KONE.  
VR technology can optimize these processes by facilitating both asynchronous and synchronous collaboration activities within a simulated virtual environment and provide access to virtual prototypes throughout the method development process. Whereas the preceding study [31; 32] investigated and demonstrated the usefulness of VR for asynchronous collaboration scenarios (where the departments were accessing VR in a sequence), this study is focused on synchronous collaboration practices. In particular, it explores the role of the synchronous collaboration scenario 1 at the phase \"outline preparations\" (see Figure 3), which may potentially minimize the misinterpretations and communication problems in the later phases of the maintenance method and technical documentation creation. In this scenario, both departments can jointly access virtual prototypes for the first time, exchange knowledge and generate digital content together, e.g., text and pictures, that can be re-utilized for technical documentation creation.