Multimedia courseware for teaching of rapid prototyping systems AbstractPurpose – The purpose of this paper is to detail the development of a multimedia courseware that enhances the learning of rapid prototyping among professionals, senior year and graduate students. Design/methodology/approach – The design and development of the multimedia courseware is based on a “visit a science museum” concept where each topic can be accessed depending on the interests or the needs of users. Factors that influence learning curve such as structure of information, application of visual and auditory components and human–computer interface are addressed and discussed.Findings – Instructions using multimedia significantly enhances the education process of rapid prototyping technology. Methods to produce a good multimedia courseware have been introduced. Originality/value – This paper describes the latest version of the multimedia courseware which is an accompaniment to the third edition of the book entitled “Rapid Prototyping: Principles & Applications” to be published in 2009.

Keywords CD-ROM, multimedia, learning, education, rapid prototyping

Paper type Research paper

1. Introduction

Multimedia refers to a computer-based communications method that incorporates visual imagery, text, video, sound and animation to create an interactive and lively presentation. Simultaneously stimulating human senses of vision and audition, multimedia is extremely effective in conveying ideas and bringing concepts to life. From educational theory, people learn best when they are actively engaged rather than passively absorbing the information (Oliver and Herrington, 1995). It is also established from educational studies that visual and auditory presentations as well as interactivity can increase the information retention rate, thereby greatly increases the slope of the learning curve to master a subject. Multimedia courseware also creates knowledge connection by linking to the internet (e.g. web links), which allows users to efficiently obtain cross-references directly.

Unlike traditional teaching methods, multimedia learning enables the learner to control his or her own pace of learning. In an interactive multimedia presentation, learners are free to navigate through the contents and select the sections that they want to learn, thus optimizes the use of classroom time. Such user control is proven to create a number of positive gains, including elevated motivation, strong self-determination and increased achievement gained over more structured forms of the same information (Oliver and Herrington, 1995).

Another distinct advantage of multimedia is its high level of customisation, in which it provides the users with several options to decide how materials (such as visual, audio, textual) are presented. A single multimedia courseware therefore can be adjusted to address different users’ learning styles and needs.

The subject to be presented, rapid prototyping (RP), bases largely on science and technology. Rapid prototyping, also known as solid freedom fabrication, is a general name given to the family of modern fabrication processes developed to build three-dimensional engineering parts in a very short lead time (Mikell, 1999). Utilising layer-by-layer build strategy, it is able to overcome the limitations and long machining times of conventional fabrication processes, such as milling and shaping. Despite its great advantage and key role in modern manufacturing process, RP is considered a new technology and thus remains relatively unknown.

To fill in the gap of knowledge on this topic, a number of RP books (Beaman, 1997; Chua et al., 2003c; Jacobs, 1992; Pham and Dimov, 2001; Anon, 2008) have been written to present this technology to industry professionals and students in senior year and graduate college education. However, due to their static nature, the books cannot convey the highly visual and technical nature of RP technologies effectively. These limitations can be overcome by adopting a multimedia approach, in which key concepts can be brought to life via the provision of a highly interactive environment.

An interactive multimedia form has been used to effectively present the concepts of RP condensed into a CD-ROM for ease of use. Learners can utilize the multimedia CD-ROM as a supplement to the RP book written by Chua, Leong and Lim (Chua et al., 2009), or as an educational material on its own.

This CD-ROM is a third edition, whereby the first and second editions were respectively published in 1997(Chua et al., 1997c) and 2003 (Lim et al., 2004b). It therefore includes a number of improvements over the earlier versions.

This paper discusses the multimedia approach in teaching RP technologies, followed by detailed elaborations and techniques used in various chapters presented in the CD-ROM. An evaluation and preliminary assessment of the multimedia package will conclude the paper, with recommendations on how future efforts can help to enhance the CD-ROM.

2. Rapid prototyping technology

Due to the market globalization, design and manufacturing companies today are moving towards international trade, where they have to compete not just locally but also internationally. Thus, it is crucial for the companies to distinguish themselves among the pool of competitors, and a fast time-to-market is one of the deciding factors.

In the manufacturing industry, productivity is measured by how quickly and cost-effectively a product is developed from initial concept to the end market. It is found that a high percentage of manufacturing costs are typically spent on designing a product (Stier and Brown, 2000). This is where the application strength of the RP process is realised. By using RP, a component which once took weeks and months to prototype can now be produced in a matter of days or even hours. RP not only allows more effective visualization, earlier functional testing and on-time verification of the end-product but also allows quick and easy modifications to the part before it is mass produced. As a result, companies can enjoy a much-needed edge over their competitors by faster turn-around time, higher quality products and minimizing costs.

Not only helping to shorten the product development and manufacturing cycle, RP has extended its application to the architect world by producing scaled building models, to the art world by creating complex sculptures, and even to forensics for investigative analysis.

Depending on the capability, processing techniques, materials and software support, there are more than 80 different RP systems available today (Anon, 2008), which can be categorized into liquid-based, solid-based and powder-based RP systems. Most of these RP systems generally adopt the following standard processing steps to produce a part:1. Create three-dimensional computer-aided design (CAD) solid modelling of the part to

be produced.2. Convert the CAD files into a RP industrial standard data file format.3. Import the data file into the RP program of that system.4. Check for errors and missing data in the data file. Perform corrections where

necessary.5. Digitally slice the three-dimensional CAD solid model into horizontal layers.6. Send the sliced data to the RP machine for production.7. Post-process the prototype, such as removing redundant materials, cleaning and

surface finishing (e.g. sanding and painting).Variables such as the type of materials used, part size, layer thickness, complexity and the

choice of RP systems greatly influence the process, time required and costs for the entire RP process.

3. Development of the multimedia courseware

Standardized throughout the CD-ROM, the courseware is organized such that the fundamentals of each chapter are presented first, followed by more advanced and detailed information.

Learners, however, are not restricted to go through the CD-ROM in that fixed hierarchy. They can select and advance directly to the chapters or subtopics that are of their interest. Such an approach is particularly helpful if the user intends to make selective references. A site map, for example, provides users with quick and easy direction and access to the chapters and subtopics. It also allows the learner to have an overview of the courseware hierarchical structure, as shown in Figure 1.

Figure 1 The courseware site map showing and allowing direct access to the main chapters and their subtopicsTake in Figure (1)

Tay (1994) suggested that multimedia is the woven integration of text, graphic art, sound, animation, and video that can create, store, transmit and retrieve both visual and auditory information. A good multimedia production should qualify the following phases: Identification of target audience. Creation of logic flow chart or navigation map. Design and development of user interface graphics, animations and sounds. Testing and debugging. Packaging.

As early as the start of a multimedia production, the target audience must be clearly identified, which will directly affect the media requirements and project planning. It is at this stage that the designer decides on the theme and objectives of the production to meet the needs of the target audience. The multimedia courseware discussed here targets the following groups of audiences: College students at the senior, graduate or higher academic level who are studying or

researching in RP. Lecturers and professors who specialise in RP or utilise it as a supplementary media for

their teaching materials. Industrial professionals who need to be educated or updated on RP systems. Individuals who are interested in the development and trends of modern design and

manufacturing technologies.The second stage of a multimedia production involves the development of a logical but

hierarchical flow chart (or a navigation map). Considered as the most important task executed in the early stages of planning, the process aims to generate a navigation map that enables designers to have an overview on the entire structure of the courseware. The navigation map, besides outlining the links among different contents, also suggests a logical flow for the interactive interface.

Figure 2 schematically depicts a hierarchical structure of one of the chapters (Chapter 5) in the multimedia courseware. In the flow chart, both the chapter sub-sections and their inter-relationship are simultaneously presented.

Figure 2 Hierarchy structure of Chapter 5Take in Figure (2)

After the goal and scope of the development has been identified and clearly understood, the design phase follows. This phase involves the specification of the content and the development of user interface, animations and sounds. Normally, not only the appearance of the material on screen but also the entire layout of the courseware is dependent on the content. The user interface, on the other hand, defines the ways in which the user interacts with the program. There are two kinds of elements in the user interface design: structural and cosmetic (Chua et al., 1997c), in which the structural element defines how information is structured and linked and the types of functions that are being provided at each point of the application.

There are many ways of presenting text and images in an interactive manner. One possible and effective method is to create interactive texts within images, whereby users hover the mouse over the images in order to obtain further explanation or information. This approach provides a user an overview of the section before he or she decides to access the selected images for more information on the content. An example of this is shown in Figure 3, where images have concealed explanation that is only exposed by mouse hovering over the selected area (commonly called “mouse over”).

Figure 3 Mouse-over mage icons with hidden information attached to each animationTake in Figure (3)

Generally, a good design aims to enhance human–computer interface by effectively conveying ideas while balancing between functionality and usability of the program. These goals can be achieved by organising the content to meet the following requirements (Chua et al., 1997c): Good information balance, Good visual balance, Simplicity and functionality of design. Information is well balanced when it is able to draw users’ attention to more important

information, while de-emphasizing those that are not of significance. It is vital to ensure that display is visually appealing and the selected colour scheme promotes clarity in the delivery of the information. More importantly, the layout of the user interface should be consistently

clear and concise, so as to prevent the users at any point from being confused about the functions of the program.

In the multimedia courseware, buttons and icons are fully utilised and incorporated to create a user friendly and easy to navigate interface. Depending on the clarity, usability and consistency inherited in these navigational tools, users can retrieve the information in a simple, easy and speedy manner (Scott, 1991). An interface, when poorly designed, will result in a lengthy search for the desired function or information (Henninger, 2001). The courseware interactivity is performed by the computer regularly asking, receiving feedback and responding to the users. This is done by having the users frequently prompted to act on the information through the use of icon and button designs. The design, size as well as the colour of the icons and buttons therefore should be simple and self-explanatory.

Colours, on the other hands, can be used to capture and retain the user’s attention. With appropriate selection, colours will create a powerful visual impact that not only enhances the presentation of materials but also promotes the interaction between users and the multimedia interface. To highlight important information and to comfort the users’ eyes, bright colour backgrounds are often used with dark colour text or vice versa. For instance, a white background contrasted with black texts and dark colour images on the screen would create a simple but attractive medium for learning. In addition, a good colour combination should be able to inform users on the current status of the program. A colour-changing buttons, for example, provides feedback to the user that some form of activation has taken place. Taking into account these factors, the courseware display (See Figure 4) is both clear and attractive.

Figure 4 Display of Chapter 7 with navigation bar at the sideTake in Figure (4)

It is important for the visual display to capture user attention. As such, the colour schemes selected will depend a lot on the target audience as well as the theme and objectives set out by multimedia team. Although can be used sparingly, colours should be applied appropriately to match the contrast with screen design and other features of the courseware user interface. By that way, the user’s eyes feel soothed and comfortable when viewing the courseware, while the clarity of information is well maintained.

Animation can also be applied to create additional visual impact to the multimedia project. One example is the use of an eye catching flickering word to stress important information. Pure animation, however, cannot stand alone (Chua et al., 1997c). Instead, it should be effectively combined with sound or supplemented by video, which brings ‘life’ to the entire program and creates more excitement.

Last but not least, an appropriate sound track should be carefully selected. When synchronized with the animation, the sound not only enhances the application but also brings about greater reality and liveliness to the presentation.

4. Design of the RP multimedia courseware

The multimedia courseware mainly aims to stimulate the user learning of RP system by enhancing the visualization as well as providing interactive environment for the target audience specified earlier.

The hardware configuration needed to run the program includes a personal computer (PC) with at least 8 megabytes of random access memory (RAM), a quad speed (4x) CD-ROM drive, a display monitor with a minimum of 256 colours and a resolution of 640 x 480 pixels or higher, a video display card (capable of the above resolutions) and speakers. The program is executable in the Microsoft Windows environment (Windows 95 or higher). A media control interface (MCI) compatible sound card or Motion Picture Expert Group Layer 3 (MP3) audio is required to play the sound files (WAV).

It is possible for the learning curve to be enhanced with the aid of meaningful and attractive visualizations. As such, the courseware interface is designed to miniaturize the interior of a science museum, where teaching content is displayed through various exhibition rooms.

Learning Rapid Prototyping through the courseware would become as joyful and exciting as walking through the museum. To promote users’ interest as well as to enhance their understanding and learning of RP process, the display theme is unique depending on the selected topics. Several room designs thus serve to cater to each theme. Consequently, there are 20 room designs in total to sustain users’ interest in the courseware.

In addition, each room contains a unique set of furniture and decorations. Those objects are icons which, on a simple mouse click, will reveal its diverse hidden content, such as quizzes, video or details on the corresponding topic. Users therefore can enjoy the mysterious environment and at the same time have their curiosity stimulate to learn more about the explanation concealed within it.

By exploring different rooms of the science museum, learners subconsciously gain knowledge on Rapid Prototyping. In this way, the pressure and boredom usually found in traditional ways of learning is eliminated, which enhances the whole learning process.

Through creatively adopting various themes to stimulate users’ excitement, the courseware maintains the attributes of being well organized and consistent. Each chapter display is standardized by starting with an entrance room, of which the right and left sides lead to two other show rooms where the users can find more detailed information on the selected topic. There is also a ‘tour guide’ at each chapter entrance, who is characterized to synchronize with the corresponding themes. Not only providing the users with instruction and introduction on the chapter, the friendly ‘tour guides’ also bring joy and breathe life to the program, which helps to sustain the users’ attention and excitement. For example, in Chapter 5, users find themselves exploring the themes of magic and have fun observing the tour guide- a Magician- introducing himself and giving instructions on powder-based RP systems, as shown in Figure 5.

Figure 5 Chapter 5 entrance with a Magician mascotTake in Figure (5)

Designed to be both user-friendly and interactive, the multimedia CD package allows the users to easily navigate through the program in just a few mouse clicks. The program begins with an entrance introduction room, which directly leads to the main menu. Creatively resembling a road map, the main menu prompts the user to select the topics or chapters to be explored. There are eight chapters displayed in distinguished exhibition themes (Figure 6):1. Introduction – the Science Museum’s main entrance 2. RP process chain – a Gallery3. Liquid-based RP systems – a Laboratory 4. Solid-based RP systems – a Pirate’s hideout5. Powder-based RP systems – a Magician’s vault 6. RP data formats – an Egyptian exhibition hall7. Applications – a Robot’s residence 8. Benchmarking and Evaluation– a Seminar room

Figure 6 Different display themes for: (a) Chapter 1; (b) Chapter 2; (c) Chapter 3; (d) Chapter 4; (e) Chapter 5; (f) Chapter 6; (g) Chapter 7; and (h) Chapter 8 Take in Figure (6)

Each topic mentioned above details the various important aspects of RP. Chapter 1, for instance, is the introduction chapter and gives an overview on different types of RP as well as a brief introduction on the subjects, including RP fundamentals and its historical developments.

In the chapter ‘RP process chain’, the user is presented with an insight of the fundamental fabrication methods as well as general steps exercised in the RP process. Useful especially for new learners who have little or no prior knowledge of RP systems, this chapter provides the users with the essential foundations of RP before they proceed to the later chapters.

The next 3 chapters cover the primary RP systems that are broadly categorized as ‘liquid-based’, ‘solid-based’ and ‘powder-based’ systems. There are 6 main types of RP process, of which each pair is corresponding to one RP system: Liquid-based RP systems: Stereolithography Apparatus (SLA) and Polyjet Solid-based RP systems: Laminated Object Manufacturing (LOM) and Fused

Deposition Modelling (FDM) Powder-based RP systems: Selective Laser Sintering (SLS) and Three-Dimensional

Printing (3DP)Going through the chapters, the users are provided with the detailed information of the RP

systems, including the related company and products, the processes and the underlying principles, their respective strengths and weaknesses, applications and examples. The sections are easily selected through the use of the side navigation bar (see Figure 7).

Moreover, videos and stills are also included in the program, which aids to enhance the user’s visualization and attention.

Figure 7 Detailed explanations are viewed by selecting suitable navigation barTake in Figure (7)

The sixth chapter, ‘RP data formats’, introduces and discusses the advantages and disadvantages of various translators that are available for use by RP systems (Chua et al., 1997a, b), such as the industrial standard STL file format. Other newly proposed data formats (Gan et al., 1999), such as stereolithography contour (SLC) (Ngoi et al., 1993) and common layer interface (CLI), are also included in this chapter. In addition, it is here that users can have an insight into the various ways of tessellating a model as well as various aspects of software-related information, such as possible problems while converting the CAD file to the STL file, how to check for such errors and how to correct them (Leong et al., 1996a, b). The main purpose of the chapter is therefore to provide the learner with a complete picture on the converting methods and data formats available in RP.Under chapter 7 ‘Applications’, users are presented with a more in-depth illustration of RP technology in various disciplines (Chua et al., 1999a), including design, engineering, analysis and planning as well as manufacturing (Cheah et al., 2002a; Cheah et al., 2005; Chua et al., 2005; Du et al., 2002; Lee et al., 2004) and tooling (Chua and Ngoi, 1992; Chua et al., 1999b, c). These descriptions aim to emphasize that RP has a wide range of applications rather than merely being restricted to the manufacturing industries. Several finishing methods in RP process are also mentioned and discussed. Moreover, in this chapter, users can learn more about many applications of RP in different industries, such as aerospace, automotive, creative, medical (Creehan and Bidanda, 2006; Gibson, 2006; He et al., 2008; Lim et al., 2008; Ma et al., 2001a, b), bioengineering (Chua et al., 1998a) and Geographic Information System (GIS). Among these, RP plays a key role in the field of medicine and bioengineering, where it provides important assistance in planning and simulation of complex surgery (Chua et al., 1998b; Lim et al., 2002; Lim et al., 2004a), customizing implants (Ang et al., 2007; Cheah et al., 2004; Chua et al., 2003a, b; Chua et al., 2004; Leong et al., 2002, 2003; Naing et al., 2005; Tan et al., 2003; Tan et al., 2005a; Tan et al., 2005b; Yang et al., 2001, 2002; Yeong et al., 2004; Yeong et al., 2006, 2007; Wiria et al., 2007) and prostheses (Cheah et al., 2003a, b; Chua et al., 2000), design and production of medical devices (Ang et al., 2006; Boland et al., 2007; Cheah et al., 2002b; Chou et al., 1998; Chua et al., 1998c; Leong et al., 2001; Leong et al., 2007; Liew et al., 2001, 2002; Low et al., 2001; Ramanath et al., 2007; Too et al., 2002), forensic and anthropology as well as visualization of bio-molecules. In each industry, several examples are discussed to give the users greater understanding on the benefit of RP. The creative area, for instance, has RP to be used in jewellery (Chua and Gay, 1991; Lee et al., 1992), coin mint and tableware (Chua et al., 1993) industries as well as architecture and arts (Wang et al., 2006).

Lastly, the chapter on ‘Benchmarking and Evaluation’ covers various aspects of the RP benchmarking process, its reasons and methodologies (Chua, 1994; Chua and Leong, 1997; Chua et al., 1998d; Kochan and Chua, 1995; Kochan et al., 1999). Not only exposed to

different models types and measurement standards used in benchmarking, the learners are also guided on how to record the data and

analyze the results properly to come out with a good benchmarking conclusion. A specific case study has also been included in the chapter, which aims to enhance the users’ understanding and learning through practice.

Except for the ‘Introduction’, each chapter has at least one or more sets of quizzes (see Figure 8). By solving and checking answers for the quiz questions, users are given an enjoyable opportunity to revise, consolidate and eventually better retain the newly learned knowledge. The quiz is designed and programmed so that the sequence of questions, as well as the order of multiple-choice answers, becomes different each time the user attempts it. Consider a quiz system of 10 multiple-choice questions randomly arranged, each having 4 possible answers in an unfixed order, there are therefore 87,091,200 setting variations available. This enormous number of possible permutation makes it even more challenging for users who want to take the quiz, and hence gives them a more accurate assessment of their understanding of the subject. Feedback is also given to the users with evaluation on their answer and their overall performance in the quiz.

Figure 8 Answer review to quiz questions in FDMTake in Figure (8)

In exploring all eight chapters in the courseware, users have an option to return to the main menu, seek for help, turn on or off the sound, view a glossary, or exit the program at any point. Simple and easily understandable, those function buttons are standardized throughout the courseware, which enable easy recognition and access whenever a need arises. The Help icon, for instance, is symbolised by a question mark ‘?’ that allow the users to catch the function of the buttons immediately. Upon selection, the Help section provides users with several options to choose as well as corresponding instruction depending on the users’ request.

Throughout various stages of the CD-ROM development, the courseware appearance and performance are continuously tested and evaluated to make sure that the bugs and errors are rectified at early stage. The testers’ comments are carefully recorded and documented for later reference. Also during the test assessments, the CD-ROM has been shown to be able to satisfy a wide range of users. The testers agreed they were comfortable with the multimedia interface, enjoyed the quiz and were largely attracted by the animation, video, images as well as the colour combination of the program. They, however, commented more favourably on more interactive components such as games and challenges to bring up the excitement. Further work thus needs to be carried out to improve the performance and functionality of the future version of the program before its next release to the general public.

5. Conclusions

Overall, the multimedia courseware creates a virtual platform that allows the users to learn, visualize and evaluate different RP systems and their applications without the aid of any physical hardware.

Richer in audio, visual and interactive components such as sound and animation, this multimedia courseware is a significant improvement over the previous versions. Nevertheless, there is still room for further improvement. Future development could emphasize on the graphical appearance of the display and animations, which can make it more believable and lift up the overall quality of the courseware. The graphic, however, highly depends on the technology in hand and thus will mostly be decided by the time of production.

Consequent work could also involve the use of audio guide to enhance the learning process. Apart from the display design that provides information in visual format, the voice guide acts as a reinforce input that presents the same information using audio signal. Simultaneously learning through both optical and auditory channels, users therefore can absorb and retain knowledge covered in the courseware more effectively.

In addition, a search engine for the multimedia program could also be a good and useful feature, as it will assist the users in locating their particular sections of interest by using keywords. Quick and simple, this additional function will serve a wide variety of users; thus making the courseware even more attractive and user friendly.

It must be stressed, however, that textbooks and traditional live lectures still remain important and indispensable. Due to its typical limitations, the multimedia CD-ROM is only an auxiliary means to convey the main concepts of RP presented in the books rather than substituting the physical ones. The CD’s greatest benefit perhaps lies in its ability to allow users to learn at the comfort of their own pace and time. Immersing in the courseware’s multimedia and interactive environment, users are able to visualize and therefore rapidly capture the RP concepts, which is impossible or hard to achieve when reading the books only.

With the fast pace of development, today’s technology is capable of producing high-end multimedia products that can greatly enhance and shorten the learning curve. There are increasing numbers of educational institutions and software developers who create multimedia courseware for educational purpose, mainly to assist students and lecturers in learning and teaching process. Due to it highly visual and technical nature, rapid prototyping (or RP) is rather lengthy and difficult for students to gasp only through textbooks. Thus, the multimedia courseware of this subject becomes important in making learning about RP technologies simpler and more joyful.

Besides academic application, the multimedia courseware also provides a quick access for busy engineers and marketing personnel who need to check relevant information on RP. Moreover, the program becomes useful for keen learners who want to keep their fingers on the pulse of RP cutting edges. This explains why continuously updating on existing data as well as gathering new information about RP plays a key role in the development of this multimedia package.

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Corresponding author

Chua Chee Kai can be contacted at MCKCHUA@ntu.edu.sg