# VR as a 3D Modelling Tool in Engineering Design Applications
## 5 Conclusions  
The research objective of this work was to investigate whether VR 3D modelling can be used after the conceptual design phase to bridge the gap between the concept and product's final form (model) in the engineering product development process. Currently, desktop CAD modelling is being used for this purpose, but it is a time-consuming process, where multiple issues arise, especially if the product has a complex geometry. VR technology enables the users to be immersed in the design environment and offers more liberate geometry manipulation, therefore it shows great prospects for modelling purposes. To further explore the main research question, different parameters were considered including the possibility of converting a VR-created model into a sold CAD model and the usability of VR modelling tools in terms of speed, intuitiveness of the tools and the modelling process, as well as the output model quality.  
It was found that VR modelling is intuitive, fast, and offers better spatial perception/visualisation for users and enables the transition from concepts to detail design. However, when compared to the desktop modelling tools, VR lacks precision which leads to increased inaccuracy in the created 3D models. Also, it was found that current VR toolsdo not provide suitable features for creating technical objects with simple, elementary geometrical shapes, and that they can be created faster and with greater precision in desktop modelling applications. Another important missing feature in VR is the inability to define relations between the elements (e.g., parallelism, distance, etc.). Based on these findings, it was concluded that VR 3D modelling in the current state is not yet a suitable technology to provide adequate support for mechanical engineering design applications. However, VR modelling proved to provide a quicker alternative for creating freeform models, which have more complex, organic forms. An advantage of modelling in VR is that the control vertices of the surfaces are more easily distinguished from one another because of the added depth of the VR environment. This has a significant impact when dealing with more geometrically complex models. Along with the fast-learning capabilities and intuitiveness of the use, this feature also indicates that the tool has potential for teaching purposes as it leverages the 3D visualisation to improve the spatial perception and the understanding of the structure of the surface (control vertices and curves) more clearly.  
In further research, the technology could be tested in different stages of the product development process, and for different activities in product design, such as ideation and conceptualisation without a predefined design, for which the tools offer more advantages. Several advantages in the field of education were identified. To properly evaluate the educational prospects of VR 3D modelling different metrics should be considered to e.g., measure interestingness, fun, engagement, and knowledge transfer efficiency. Finally, the VR 3D modelling process could be tested by engineering professionals from the industry to obtain feedback from the real industrial use cases.  
Conceptualization, D.V., V.C. and U.U.; methodology, D.V., V.C. and U.U.; software, U.U.; formal analysis, D.V.; investigation, D.V., V.C. and U.U.; resources, D.V. and U.U.; writing--original draft preparation, D.V.; writing--review and editing, D.V., V.C. and U.U.; visualization, D.V. and U.U.; supervision, V.C.; project administration, D.V. and U.U. All authors have read and agreed to the published version of the manuscript.  
This research was partly financed by the Slovenian Research Agency ARRS (MR No. 51899) and partially with support from the European Commission Erasmus+ project 2018-1-HR01-KA203-0 47 486.  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
The authors declare no conflict of interest.