Intra-Document Links

9/30/99

Intra-document links are special links that allow you to define jump-to points within a single document. To create one requires to things. You must define the jump-to points using <A NAME="somename"> and then define the links to those points using <A HREF="#somename">. You can also reference jump-to points that exist in other documents. For example, imagine that you want link to an anchor point called myplace in a document called mydoc.html. After you have created the jump-to point in the document called mydoc.html, you reference it from a different document using <A HREF="mydoc.html#myplace">.

The example below shows how these are done.


Links
An Instructional Method for the AutoCAD Modeling Environment
James L. Mohler
Department of Technical Graphics
Purdue University

Abstract

This article presents a command organizer for AutoCAD to aid new users in operating within the 3D modeling environment. While teaching solid modeling as the basis for engineering design, as well as a using the modeling database as a focal point for the generation of other types of technical and engineering graphics, it was found that new users frequently encountered the same problems and asked the same questions when presented with the 3D environment. The organizer presented in this article is designed to help engineering students become acquainted with the AutoCAD modeling environment and the commands that control the environment; it has met with limited success in both visually organizing the command structure and decreasing new user questions. Although it is specifically designed for the AutoCAD environment, it must be noted that the underlying environmental controls and the operation of the environment is consistent and applicable to many other software packages and graphical applications.

Introduction

The use of three-dimensional environments in engineering education has drastically changed the way engineering graphics concepts can be presented and taught.  Three-dimensional modeling enables engineers and designers to work in a realm that on paper can so easily evade them.  As educators continue to increase the implementation and use of computer modeling tools, they continually request more and more features in their desktop CAD software.  In doing so, the interface and other aspects of the software become more complicated for new users.

As engineering educators, we ourselves have no doubt gradually migrated to the modeling package of our choice.  Often this migration occurs in small, incremental steps over several years of our professional career. Unfortunately, for students, the introduction to 3D tools is foreshortened. Students must become accustomed to the software tools much more quickly for success in the limited amount of time they have in the computer laboratory.  Many times students struggle to not only learn a new software, but also to adapt to the three-dimensional environment and the graphics concepts being taught.

As modeling continues to become a larger part of engineering education, often it is difficult to separate theory instruction from tool instruction.  Much classroom time is spent teaching tool specific techniques rather than more global, conceptual matters. Techniques and procedures in model manipulation are a daily occurrence because tool instruction is important in the day-to-day nature of the tasks and projects the student must execute.  But the optimum is to be more than teachers of a software tool.  To empower students, engineering educators must help students overcome the learning curve of new software and the modeling environment so they may conscientiously attend to learning concepts.

In software such as AutoCAD, new users are often intimidated by the wealth of commands, not to mention the three-dimensional working environment. Many of these 3D modeling packages have evolved significantly from version to version, with very few features being removed.  The evolutionary nature of the software presents the student with several complex paths to get from A to B; some being more efficient than others.  This nonlinear characteristic makes the CAD software an inhibiting and unstructured environment for new or casual users.

In addition, educators continue to involve students with the modeling paradigm earlier in their education. Several sources state that early introduction to modeling increases visualization skills. Likewise, many have departed from traditional board-based descriptive geometry to modeling environments to teach visualization (Bertoline 1991, Devon, et. al. 1994, Sexton 1992).

The focus of this paper is not to debate these issues, but rather to acknowledge that early introduction to computer modeling and the 3D environment compounds the number of cognitive skills being concurrently developed, particularly if computer skills are waning. Engineering educators must analyze the possible attributes that make the 3D environment difficult for students to use, as well as the various teaching aids that can assist the student in understanding and becoming efficient in the operational 3D modeling environment. By endeavoring to decrease the software learning curve through the use of mnemonic devices, organizers, multimedia and visual descriptive aids, students can more easily focus on the process instead of the tool or environment.  Enabling students to move beyond the software should be a goal; allowing them to focus on visualization and spatially-focused analytical skills.  In reality, anything engineering educators can do to help the user cognitively arrange and understand the 3D environment and software commands lowers the learning curve and empowers the student.


Analyzing the Problem

To begin creating efficient and effective tools or aids for instruction the problems associated with learning a 3D tool must be analyzed. A review of literature points out that there are many factors that can contribute to the difficulty new users have with a 3D environment. Let’s face it, students who can now interact and build almost anything within the virtual universe contained within the desktop computer are not used to being able to draw or operate within a virtual 3D environment. Previous drawing experiences of most students are almost certainly limited to drawing in two-dimensions. Experiential conditioning to be “flatlanders” has prepared most students to think in a two-dimensional manner, always striving to find a way to draw in three-dimensions when they only have two with which to work. Three-dimensional environments contradict the traditional drawing and sketching paradigm that students have been presented and for which they have been conditioned. This alone presents students with a learning curve that is quite pronounced when it comes to 3D environments. Not only must they deal with the environment but they must also learn to control it. Yet there are also other factors that contribute to the difficulties of today’s 3D modeling environments.

Visualization Skills
In addition to the tremendous shift in paradigms, another problem is that many students have little visualization ability. To present students, whose visualization skills are waning, with a 3D environment can be disastrous because they often do not have spatial visualization or spatial orientation abilities. Yet, one does not have to subject a student to a 3D environment to see this weakness exhibited. In most instances, visualization ability can be revealed through the use of imaginative sketching exercises as well as specially designed tests which reveal the level of spatial proficiency within the student. Engaging a student, weak in visualization, with a 3D modeling environment only magnifies the student’s visualization weakness.

The study of visualization ability and its affect on the student has a long history in many professional societies. As described by Miller (1996), visualization has long been a part of the information disseminated throughout the Engineering Design Graphics Journal. One of the most intriguing factors, at least to this author, is the role that imagination plays in visualization ability. Many of the sources discussed by Miller, including prominent historical individuals in the field such as Orth (1941), Blade (1949), and Kliphart (1957) state that imagination is primary to visualization ability. It would seem natural (and is pointed out by these sources) that the ability to imagine familiar objects such as a chair, table or other item is a precursor to being able to visualize an object based on orthographic multiviews. It would also stand to reason that imaginative ability would be a precursor to operating within a 3D environment which requires spatial visualization and orientation abilities.

Within our own decade, the impact of imagination can be seen through suggestions for curricula and media tools to aid in teaching visualization. Wiley (1990), Wiebe (1993), and Ross & Aukstakalnis (1993) suggest that the use of real models, animations, and virtual environments can aid in teaching or enhancing visualization ability.

It seems that as technology continues to increase in its ability to entertain students, imagination is used less and less by students. Students become used to being entertained rather than imaginatively entertaining themselves. Therefore, the imaginative skill is undeveloped. Does a decreased use of imagination decrease potential visualization ability? Although research is needed to validate this point, it is intriguing to consider that a loss (or decrease) of a historically noted precursor to visualization -- imagination -- could be one of the reasons a greater number of students have difficulty with visualization, and consequently, operation within a 3D environment. It will be interesting to see the impact that computer technology such as the World Wide Web, Virtual Reality Modeling Language (VRML), and the 3D human-computer software interface has on the visualization skills of the next generation of engineering students. If 3D technologies infiltrate the younger generation, visualization skills may be more refined within entering freshman -- if not as a result of imagination, then as a result of experience.

Nonlinear Tools
Another possible contributor to the problems that students have with the AutoCAD modeling environment is the way in which they have access to the commands that control the 3D world, as well as the way in which those commands are presented in the educational setting. Much of this is related to the ability to perform any number of operations within the 3D environment at any given time -- the software’s nonlinear attribute. For example, at any time, an object can be rotated or moved. At any time the view of the database can be rotated or moved. The coordinate plane can also be positioned anywhere at anytime. This scenario presents the student with a unstructured or independent mode of operation. Most often students become disoriented as a result of unstructured control -- too many variables...........................


Jumping to a Target in Another Document

This link is set up to jump to a target in another document. Note the document doesn't actually exist.