PRUEBAS DIAGNÓSTICAS DEL APARATO LACRIMAL

As before, in order to collect participant feedback from the trial, one questionnaire was designed for the designers (see appendix V) and a different questionnaire designed for the users (see appendix VI).

Outcomes of the questionnaire to the „designers‟

The first group of questions were general questions regarding the designers‟ background and experiences

157

The first question was “Have you ever used Rhino in a designing activity and if not, what kind of 3D modelling software have you used?”

According to the responses, none of the eight designer participants had ever used Rhino to create a CAD model. However, they had used other types of CAD modelling software packages, such as Pro/Engineer, Autodesk, Alias, 3D Max, SolidWorks, etc. This meant that all the participants had to adjust the CAD model without previous experience in using Rhino. However, none of the participants found this to be a difficult task.

The second question was “Have you ever built a physical mock-up to test one of your designs and if yes, what aspects have you tested with it?”

Except for one participant, everyone answered “Yes” to this question. Regarding the aspects that they had tested with a mock-up, the participants were asked to choose multiply from ergonomics, functionality, aesthetics and others. Figure 75 shows the frequency of the choices.

158 0 1 2 3 4 5 6 7 8

Ergonomics Functionality Aesthetics others

The aspects that have been tested with the mock-up

N um be r of pa rt ic ipa nt s

Figure 75: The aspects that have been tested with the mock-up

The figure shows that physical mock-ups were most often used to test ergonomics issues. Besides that, functionality and aesthetics were also commonly tested with physical models.

The third question was “Have you ever built a CAD model as well as a physical mock-up for one of your designs and if yes, have you ever used both of them simultaneously to test your design?”

All the participants said they had built a CAD model as well as a physical mock-up for at least one of their designs. However, only one participant claimed he had simultaneously used both of them to test his design. The example he gave was in the analysis of a new car control system, where the real model worked simultaneously with a simulation in the SAMMIE CAD system. However, it was found that SAMMIE itself is a computer based

159

Human Modelling tool [SAMMIE.com 2011]. In another word, it is just a virtual prototyping tool. There is no evidence showing that there is direct and real time connection with physical prototype.

The second group of questions was only relevant to the “Connected” mode of the trial. They were aimed at collecting feedback on the proposed integration method. The first three questions were answered on a five point Likert scale where 1 was the most negative response and 5 the most positive. Each question was followed by a space on the questionnaire where participants could give an explanation for their answer.

The first question was “How do you feel about the ease of operation of the CAD model?” Figure 76 shows the spread of the responses.

0 1 2 3 4 5 6 7 8

level 1 level 2 level 3 level 4 level 5

Very difficult---ok---very easy

N um be r of pa rt ic ipa nt s

Figure 76: How the participants felt about the ease of the operation of the CAD model

160

According to the responses, most participants chose level 3 and above and an average of 3.75 was obtained on a scale of 1 to 5 (the score was 3.5 for the similar question in the previous trial). However, one chose level 2. This person stated that the main reason for his choice was he had never used Rhino before. However, all the other participants had also not used Rhino before, but they still felt it was quite easy to operate the CAD model under the instruction, and chose levels 3, 4 and 5. This shows that the perception of ease of use can be affected both by the technicalities of the system but also by past experiences of the individual user.

The second question was “How do you feel about the level of difficulty of the process of the trial?” Figure 77 shows the spread of the responses.

0 1 2 3 4 5 6 7 8

level 1 level 2 level 3 level 4 level 5

Difficult to follow---Ok---Easy to follow

N um be r of pa rt ic ipa nt s

Figure 77: The response to the process of the trial

The responses show that most participants felt the process was easy to follow. An average of 4 was obtained on a scale of 1 to 5 (the score was 3.75 for the

161

similar question in the previous trial). There were two main reasons given for most participants choosing level 3 or 4 rather than level 5. One was they did not have experience in using the Rhino software, hence the difficulty in following the process; another was the quality of the matching between the physical mock-up and the CAD model – sometimes the CAD model was not sufficiently responsive to the movement of the physical mock-up. There might be two reasons for this. One was vibration in the physical mock-up causing the encoding elements to move irregularly between the LEDs and the sensors. Another was that the size of the holes was too large to track very small movements.

The third question was “Do you think this method is helpful in modifying your design more quickly than traditional methods?” Figure 78 shows the spread of the responses. 0 1 2 3 4 5 6 7 8

level 1 level 2 level 3 level 4 level 5

Not at all---OK---Very much

N um be r of pa rt ic ipa nt s

Figure 78: The level of the helpfulness of the method in quickly modifying the design

162

The figure shows that an average of 3.875 was obtained from a scale of 1 to 5 (the score was 3.75 for the similar question in the previous trial). Most participants chose level 4 and 5, which indicated that they recognised the helpfulness of the method in quickly modifying the design. However, the participants who thought it was not so helpful indicated that the method would only be useful when the designers need to test a product with a number of people and/or test a number of elements within the product, otherwise, it would be not necessary.

The fourth question was “Do you think this method is a valuable way of getting users more involved in the design activity and, what is the reason for your choice?”

All the participants answered “Yes” to this question. Five participants stated their reasons as follows:

1. Users can see the physical model and test it at the same time. Users can modify the virtual model through the connection.

2. They can see the changes in front of them. It is more fun.

3. It is an interactive way in designing, where users can see the impact of the test on the design.

4. Users can experience the related process of changing the design and can make their input during the process to help them better understand their needs.

163

After the above questions regarding the proposed method, the participants were asked to compare the two modes of the trial, i.e. the Connected and the Disconnected.

The first question here was “In which mode do you think the trial is easier to operate?”

All the participants chose the connected mode in which the proposed integration method was applied.

The second question was “Which mode do you think is more efficient?” Six participants chose the connected mode, however the other two chose the disconnected mode. The reason given by these two participants was similar: the accuracy of the match between the physical mock-up and the CAD model, especially when the backrest angle was tested. For example, when the backrest angle of the physical mock-up moved 13 degrees, the same element of the CAD model might have moved 15 degrees. This again highlighted the need for good accuracy between the two prototypes if designers are to be fully satisfied with this method.

There was an additional open question to ask advice from participants about this proposed method: “what other products do you think we could apply this method to and what elements could be evaluated?”

The suggested products were:

 Sports equipment

 Home appliances

 Any product that needs adjustment to accommodate people with different body characteristics.

164

 Any product that needs to consider ergonomics, such as bicycles, motorbikes, etc.

The elements that were suggested for evaluation were:

 The position of the handlebars and brakes of a bike

 Scale or proportion of a product

 The material of the product surface, such as leather for chair surface?

 Pressure

Outcomes of the questionnaire to the „users‟

Once again, the first three questions were answered using a five point Likert scale, the same as the questions to the designers.

The first question was “How do you feel about operating the physical chair prototype?” 0 1 2 3 4 5 6 7 8

level 1 level 2 level 3 level 4 level 5

Very difficult---Ok---Very easy

Number of participants

Figure 79: Ease of operating the physical chair prototype

Figure 79 shows the result that an average of 4.875 was obtained on a scale of 1 to 5 (the result was 4 to the same question in the previous trial). The

165

figure shows that most of the participants felt the physical prototype was very easy to operate. This also indicated that the new physical mock-up had been improved significantly compared to the old one.

The second question was “How do you feel the visibility of the CAD model?”

0 1 2 3 4 5 6 7 8

level 1 level 2 level 3 level 4 level 5

Very poor---Ok---Very good

Number of participants

Figure 80: The visibility of the CAD model

Figure 80 shows the result that an average of 4.75 was obtained on a scale of 1 to 5 (the result was 4 to the same question in the previous trial). This demonstrated that after the adjustment to the physical and CAD model, the match between them had been improved. As one of the users said “I can clearly see the CAD model changing following the physical one.”

The third question was “Do you think the process of the trial was easy or difficult to follow?”

166

Figure 81 shows the result that an average of 4.75 was obtained (equal to the result to the same question in the previous question). The result again showed that most users felt the process of the trial was very easy to follow. One user stated “The trial was very straightforward” and another “The process is very easy to follow”.

The fourth question was “Which mode of the trial do you prefer and what are the reasons for your choice?”

All the users chose the “Connected mode”. The reasons they stated are summarised:

 On Connected mode, the trial was easier to follow;

 The Connected mode took less time to finish the same task

 Because the physical mock-up and CAD model were updated at the same time, it was easier for the user to understand the design.

0 1 2 3 4 5 6 7 8

level 1 level 2 level 3 level 4 level 5

Difficult to follow---Ok---Easy to follow

Number of participants

167

6. 4 Discussion

In this chapter, an integration system named Loughborough University Prototyping Integration System was introduced. Although this conceptual system was not fully-functional, it has explored a novel way to achieve real time integration between physical and virtual prototypes. Because both the physical and virtual prototypes were synchronous and adjustable, the prototyping iterations were significantly speeded up. For designers, the system can help them to modify their design more quickly and easily. For the users, the real-time integration of the two types of prototypes was helpful for them to understand the design and to get involved in the testing of the design. In addition, compared to other related technologies, this system is more advantageous in compatibility with 3D modelling software packages and there was no programming work needed.

By comparing the two stages of trials presented in this chapter, it showed that after the upgrade of the system, the testing results were improved in several aspects. This indicated that technical issues were key to the performance of the system. The quality of the prototypes and integration equipment heavily influences the application of this system. To use this system, the designers would need to spend a significant amount of time and money building prototypes of sufficient quality, for example, using rapid prototyping to create a high grade physical prototype. This characteristic could be a limitation to the application of this method, especially in regard to more complex products. This aspect is addressed in the next chapter.

168

Chapter Seven

Developing a Generic Approach to Prototyping

Integration

In the early chapters of this thesis, substantial knowledge of the generic process of product design and prototyping has been presented. In the later chapters, a specific prototype integration system called LUPIS was developed and validated through several experiments. In this chapter, the remaining objective of the research is met through the development of a generic method of prototype integration that aims to help product designers working in a wide range of product sectors