International Workshop on

“New WEB technologies for collaborative design, learning and training” Turin, Italy November 13th-14th, 2003

A MULTIMEDIA CD-ROM FOR TECHNICAL DRAWING SELF-LEARNING Marco Vezzani Accademia Navale di Livorno (Italy) 5° Gruppo Insegnamento “Macchine Marine e Architettura Navale” e-mail: [email protected]

ABSTRACT Information Science is of great importance in most of the industrial, scientific, technical and financial activities. Recently the awareness that Information Science means is also precious in the didactic and educational fields is spreading around. Since 2000 the Author is the reference collaborator for the Naval Academy in Livorno as far as the realization of didactic support multimedia CD-ROMs for Technical Drawing and CAD is concerned; he also gave his collaboration for CDs in other engineering fields. The present work describes the aims, the organization and the content of an interactive multimedia CD named “Esercitazioni di Disegno Tecnico” (“Technical Drawing Training”). It was developed as a didactic support for a first level University course of Industrial Technical Drawing. Such a CD was conceived and realized in order to be an efficacious educational means of selflearning and self-valuation and to be able to satisfy the students’ need to complete their own training autonomously, following their own learning rhythms without the teacher. In order to obtain such a result, special attention was paid to the search of original solutions by matching together written texts, images, sounds, tridimensional models and animations, so that the students’ interest is arisen and they enjoy deepening their knowledge and training.

Key words : technical drawing, educational software, didactics CDs.

1. Introduction During the last years the use of computer means for educational aims has gained more and more appreciation. The Author is persuaded that the computer science may offer first class means in order to complete the traditional training and applied himself to the realization of multimedia CDs as a support to didactics. Since 2000 the Author is the reference collaborator for the Naval Academy in Livorno as far as the realization of didactic support multimedia CD-ROMs for Technical Drawing and CAD is concerned [1-5]; he also gave his collaboration for CDs in other engineering fields [6].

The present work describes the aims, the organization and the content of the last interactive multimedia CD realized by the Author and named “Esercitazioni di Disegno Tecnico” (“Technical Drawing Training”) [7]. Such a CD, actually in course of testing, will be ready in its final version by January 2004. It was developed as a didactic support to the first level University course of Industrial Technical Drawing for the first year officer students, in Normal roles, by the Naval Academy in Livorno. The CD reaps the harvest of the experience developed by the realization of two CDs which the Author has already realized for the Naval Academy, named “Esercitazioni di Disegno Meccanico” [1] and “Esercitazioni di Disegno Meccanico II” [2]. The contents of the two CDs, which have successively been revised and widened, are now in the new CD. As a result, we have a wide content CD which is able to satisfy many requirements of explanation and deepening.

2. The CD structure and goals The CD is structured into two main sections (see Fig.1). The first section, named “Theoretic knowledge”, aims to the students’ training about theoretic aspects and standard rules which are to be tested during the course and at the exam. On the other hand, the second section, named “Aided Tables”, is dedicated to interactive exercises about reading and interpreting mechanical assembly drawings and about the execution of technical drawings of part. As a whole, the CD contains more than 1000 pages connected by more than 9000 links. Such a CD was conceived and realized in order to be an efficacious educational means of selflearning and selfvaluation and to be able to satisfy the students’ need to complete their own training autonomously, following their own learning rhythms without the teacher. In order to obtain such a result, special attention was paid to the search of original solutions by matching together written texts, images, sounds, tridimensional models and animations, so that the students’ interest is arisen and they enjoy deepening their knowledge and training.

Fig. 1.

The CD index page. On the left, links to the “Theoretic knowledge” section; on the right, links to the “Aided Tables” section.

3. The “Theoretic Knowledge” section 1) 2) 3) 4) 5)

The “Theoretic Knowledge” section is organized by subjects in 5 subsections: Basic standard rules, Tolerances, Standard parts, Materials, Tests.

3.1 The subsections contents The “Basic standard rules” subsection is about the following subjects: - sheet sizes, - representation scales, - line types, - view arrangements. The “Tolerances” subsection is about dimensional tolerances. It deals with: - nominal dimension, shiftings and tolerance range; - type of shaft/hole coupling: sliding fit, interference fit, transitional fit; - ISO tolerance system; - UNI tables. In the “Standard Parts” subsection there are technical drawings, tridimensional models and designation examples of the most common standard parts: screws, nuts, pins, bearings, snap rings, keys, taper keys, etc… The “Materials” subsection is about the conventional designation of materials and in detail: - steels designation; - cast iron designation; - alloy copper designation; - light alloys designation. Finally, the “Tests” subsection is dedicated to the selfvaluation of the acquired knowledge. 3.2 The content arrangement into the subsections Each of the first four subsections contains: a) A series of lectures in Power Point format which are animated and completed by sound explanations. Such lectures summarize the most relevant aspects of the subjects present in the subsection. An example of a lecture page is in Fig.2. As an exception, the subsection about standard parts does not contain any lecture, but presents a series of html pages, any of which is dedicated to the description of a standard part. An example is in Fig.3. In particular, it must be pointed out that the selection of the part tridimensional model image allows to have access to the VRML model of the part itself. The VRML model is interactive with the students, such a chance favours the analysis of the part morphology and the understanding of its function.

Fig. 2.

Fig. 3.

An example of a lecture page of the “Materials” subsection.

An example of a page which describes a standard part.

b) Many multiple choice “assisted questions ”. Such questions have been thought of and developed in order to be an efficacious educational means of deepening and selflearning, and represent one of the original CD aspects. The questions are called “assisted” as far as, during the question examination, it is possible to take advantage of an interactive aid. In fact, the questions pages offer the possibility to (see Fig.4): 1) consult a specific selection of theoretical notions, 2) apply to a suitable “suggestion” which is able to put knowledge into action and come to a solution, 3) verify the correctness of the answer selected, 4) consult the whole solution.

c) An “elimination test” to check one’s learning. An elimination test is made of a series of ten questions and the first wrong answer causes the test to stop. When a mistake occurs, one must try and complete the test by starting from the first question again. Such a type of test has the educational function of making the students run through the correct answers again and again so that knowledge is strengthened. Such a choice has proved optimal in order to motivate students to deepen the subjects dealt with and it resulted efficacious to selflearning. The fifth subsection contains transversal tests about the subjects of the fourth previous subsections. These are “score tests”. Each “score test” is made of a series of ten questions; the final score is given by counting the right answer with respect to the ten questions. In order to encourage the interest to repeat the same test many times, during execution the partial score and the correct answer are not given. The score test aims to the selfvaluation of the reached learning level.

Fig. 4.

Example of a starting page of an assisted question and of the pages linked to it. The selection of the three push-buttons which link to “theoretical knowledge”, “suggestion” and “solution” allows to consult the due pages; the selection of one of the six numbered push-buttons allows to verify the answer correctness.

4. The section “Aided Tables” The content of the section “Aided Tables” is organized into four subsections, each of them related to one of the following mechanical assembly: 1) forming die, 2) disk valve, 3) hand remote control, 4) shearing machine. 4.1 Structure and contents of subsections The starting page of each subsection shows the assembly technical drawing to be analyzed and the assembly bar of links upwards. An example is in Fig.5a. The bar allows to activate many links concerned with the interactive reading of the assembly drawing. These are the available links and the contents description: à links to the assembly technical drawing, which is respectively entirely visible in the window, enlarged and enriched with links to sound explanations in the most complex areas; moreover, the assembly technical drawings are furnished with links to the pages of each part; à links to, respectively, front views, plan views, profile views and tridimensional views of the assembly; there are three images for each type of view; an example is in Fig.6; à links to the assembly interactive VRML models, respectively sectioned and not sectioned (in the second case some parts are sectioned to make the inner shapes and surfaces visible);

(a) Fig. 5.

(b)

Example of a starting page of an assembly (a) and example of a starting page of a part (b).

Fig. 6.

Example of the three pages of an assembly tridimensional views.

à link to the 3D animation of the assembly functioning; à link to the 3D animation of the parts tolerance coupling; à links, respectively, to the exploded model image of the assembly (furnished with links to pages about each constituent part) and to the interactive VRML exploded model of the assembly; ………

à links to the pages of the parts by selection of identifying numbers.

During the phase of the assembly interactive reading it is also possible to have access to specific information about each part. In that case, under the bar of the assembly reading links, there is a second bar with the links to the selected part. An example is in Fig.5b. These are the available links and the contents description: à links to the part interactive VRML models, respectively as a whole and sectioned; à link to a page with the front, plan, profile, right, from the low and from behind views and in the position provided for by the relative standard rules; moreover the page contains the link to the interactive VRML model of the part; the whole of it allows to analyse the correspondence between the 3D part and its relative bidimensional representation (an example is in Fig.7); à links to the part technical drawing, respectively dimensioned and not dimensioned.

Fig. 7.

Example of a page about the correspondence between the 3D model and the 2D views of a part.

4.2 Working method The CD presentation suggests the following working method for an efficacious use of the “Aided Tables” section. As a first step, using just the three links to the assembly technical drawing, it is possible to carry out one’s own “reading” phase of drawing, in order to try and understand how the machine works, its main shapes and the shapes and functions of each part. In a second time, a wide range of checking possibilities offered by many other available links allows an efficacious and exhaustive selfvaluation activity about one’s own reading abilities, which follows the learning path step by step. The possibility to accede to the very large number of tridimensional images, also with transparent effect, and to the many interactive VRML models, also of the sectioned type, to the animation of the machines functioning, to the projection views and to the technical drawings which are dimensioned or not dimensioned, etc…, makes the students’ interest grow towards a deeper and deeper examination of the machine and of its components, involving them in an extremely fruitful selflearning activity.

5. Conclusions The present work describes the contents and the aims of an interactive multimedia CD about Technical Drawing training. The CD was developed to be an efficacious selflearning and selfvaluation means at the disposal of the students, to be used by oneself, without the teacher being present. The organization of the content aims to activate interest, to make motivation grow, to improve learning quality and to reduce studying time. Previous experiences [1-6] assure a high interest and motivation to learning and to deepening knowledge by computer science means, with a consequent relevant increase of the acquired competence level. The first results, reached with the use of a trial version of the CD, were very satisfying. The Author was able to find a relevant increase as far as students’ interest and wish of deepening knowledge were concerned.

As for the future, the Author proposes to widen the subjects dealt with and to improve the content organization in order to best rouse each learning channel and the multiple intelligence, that is to say everyone’s abilities to learn by different styles, catching the linguistic-expressive, logical, iconic or sound aspect of a concept or of any matter presented in a multimedia way.

References [1] Vezzani M., Esercitazioni di disegno meccanico. multimedia CD-ROM, Accademia Navale di Livorno, 2002, CD/AN 5-4. [2] Vezzani M., Esercitazioni di disegno meccanico II. multimedia CD-ROM, Accademia Navale di Livorno, 2003, CD/AN 5-6. [3] Vezzani M., Mechanical Drawing Training by Multimedia Means. “CD Rom Proceedings of XIII ADM - XV INGEGRAF International Conference on Tools and Methods Evolution in Engineering Design”, June 3-6, 2003, Cassino, Napoli, Salerno (Italy). [4] Barone S., Culla C., Vezzani M., Modellazione CAD 3D. multimedia CD-ROM, Accademia Navale di Livorno, 2001, CD/AN 5-1. [5] Culla C., Piccinini L., Pieve M., Vezzani M., Teaching CAD using multimedia supports. “Electronic Proceedings of 12th International Conference on Design Tools and Methods in Industrial Engineering” (on Compact Disk), September 5-7, 2001, Rimini (Italy) Vol. F1, p. 17-23. [6] Vezzani M., Gabiccini M., Esercitazioni di impianti di propulsione navale. multimedia CD-ROM, Accademia Navale di Livorno, 2003, CD/AN 5-5. [7] Vezzani M., Esercitazioni di Disegno Tecnico. multimedia CD-ROM, Accademia Navale di Livorno, ready by January 2004.