## 5 Experiment 2
### Data Analysis and Discussion  
There are several reasons why the AR Pointer showed better results with respect to the time of task completion. First, when using the AR Pointer, it is possible to move the object remotely through the gesture of the mobile device without the need for the subject to directly move the object. Subjects move the objects around to the GT cube every time they used the GaS interface but they moved very little when using the AR Pointer. Next, selecting the wireframe editing box for rotation and scaling is a time-consuming task. Each editing box is very small compared to the object and it is more difficult to select such a small object in the GaS method in which the user rotates the face to position the cursor. There is also a problem with the clicking method using the tip of the finger. The subjects were confused about how much they had to bend their fingers to get a click action and conversely, how much they had to stretch their fingers to produce a release action. As a result, frequent click mistakes can occur. On the other hand, the AR Pointer is free from this problem because it uses a touch screen. Figure 7 shows the error rate between the GT and experimental cubes with respect to how well the subjects manipulated and finally registered the object. In this experiment, position, rotation and scale differences were calculated for each cube set. The position difference is expressed with a Euclidean distance. Experimental results show that a distance error of 7.97 cm occurs on average when using the GaS + Wireframe method and a distance error of 12.43 cm on average when using the AR Pointer method. The proposed method has higher error rate than the wireframe method of the HoloLens. Considering that the size of the cube used as the ground truth was 53.4 \(\times\) 53.4 \(\times\) 53.4 cm, each has an error of 8.61% (about 4.49 cm on one side) and 13.44% (about 7.95 cm on the other side) compared to one side of the cube. There are two reasons why the accuracy of the AR Pointer is lower than the existing interface. First, it is the problem of precision of mobile gestures for depth control. We set the modulation sensitivity of the ray to the pixel of the mobile touch screen and set the ray to change 1 mm when moving one pixel through the gesture. The Apple iPhone 8 used in the experiment had 326 pixels per inch (PPI), so it had about 128.34 pixels per cm (PPCM) in terms of metric units. A 1 cm displacement swipe gesture would detect approximately 128 pixels on the touch screen, resulting in a 12.8 cm ray change in a holographic 3D environment. Therefore, it was difficult to control the precise ray in the current structure. In order to solve this problem, it was possible to lower the ray control coefficient for the pixel but it would have lead to a trade-off relationship with the completion of the fast task. A follow-up study would be needed to determine the ray control factor in order to ensure accuracy and speed. Second, as remote manipulation became easier, subjects were no longer near the GT cube. When moving an object away from the individual using the GaS interface, there are two ways to move: (1) the object is moved to the remote position while maintaining the object selection or (2) the object is released after the object is selected by extending the maximum arm, moving the object a certain distance and repeating the operation. Since most of the subjects chose the former method, they could see the area of the GT cube nearby and could manipulate the object more precisely when operated at a distance. On the other hand, in the case of using the AR Pointer, there was no case in which a user moved closer to an object and manipulated the object. Rather, the subjects tried to keep the AR Pointer's distance within a certain length so that the ray of the AR Pointer could be seen clearly in the HoloLens field of view (FoV). For the same reason, the AR Pointer had a relatively high error rate in the scaling interaction.