# VR as a 3D Modelling Tool in Engineering Design Applications
## 3 Results
### Research Study: VR 3D Modelling Results  
The participants in the VR 3D modelling study all managed to create 3D models with varying success. Their efforts are shown in Figure 8. Case (a) is a reference mouse made in Solidworks. Case (b) is a mouse made by a Gravity Sketch expert user (mouse modelled in Gravity Sketch with SubD surfaces). Cases from (c) to (i) show the participants' results in order of their try. The average times of individual phases were as follows: image placement and scaling--5 min 30 s; sketching the rough outline--12 min 17 s, creation of surfaces--17 min 7 s.  
Table 3 shows the volume of the models in cm\({}^{3}\). The participant (e) visually achieved the shape, which best resembles the design intent. This is also evident from the volume, which is close to the reference volume. The participant (g) failed to scale the images correctly and consequently created an inadequately sized mouse. All other participants managed to adequately import, scale and place the images.  
The level of individual task achievement in percentages is shown in Table 4 and individual phases in VR 3D modelling are illustrated in Figure 9. The images are captured stills from the workflow of participant e. Phase (I) includes importing the images, scaling, and accurate placement. The average time for this stage was 5:30 min. Phase (II) includes the creation of the rough outline, which consists of two planar sketches and one 3D sketch, created by accurately moving the CVs in an individual axis. Four out of seven participants achieved a sufficient level of sketching the rough outline with the other three reaching a partly achieved level. The main mistake was not outlining the correct edge. The average time for this stage was 12:17 min. Phase (III) represents the creation of the surfaces. Five out of seven achieved good surface transitions and the other two reached a partly achieved  
Figure 8: VR 3D modelling participants results: solid geometry models (**above**) and zebra stripes models (**below**). Case (**a**) reference mouse made in Solidworks; (**b**) mouse made by a Gravity Sketch expert user; (**c–i**) the participants’ results.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Case** & **(a)** & **(b)** & **(c)** & **(d)** & **(e)** & **(f)** & **(g)** & **(h)** & **(i)** \\ \hline Volume [cm\({}^{3}\)] & 130.5 & 144.0 & 183.7 & 80.9 & 119.3 & 165.0 & 64.4 & 118.3 & 93.4 \\ \hline \hline \end{tabular}
\end{table}
Table 3: The volume of models in [cm\({}^{3}\)].  
level. The average time for this stage was 17:07 min. Geometry matching and surface transitions are also included in this time. Only two achieved good geometry matching, three partly achieved, and two didn't achieve good geometry matching. This can be attributed to not scaling the images correctly (case g) and not sketching the rough line accurately. Phase (IV) includes mirroring and merging of the model and exporting. All the models could be converted into a solid body. The time for the conversion was not measured since it was performed by the researchers after the participants finished the study.