Make the Leap to the Third Dimension8 Oct, 2007 By: Luke Davis
When you boil it down, 3D modeling isn't complicated -- and it can save time and money as well as improve customer relations.
In the engineering, design and drafting world, technology is on our side. CAD tools of today are a vast improvement over those of previous decades. In particular, tools that allow for quick and accurate 3D modeling of systems and equipment are moving our field forward by leaps and bounds. Yet most of the consulting engineering world remains firmly planted in 2D technology. Why? Many fear that moving to 3D will be complicated and costly, and has no direct benefit.
However, in reality these myths are just that -- myths. In fact, I'm here to tell you that making the move toward 3D will actually make life easier, save money, and improve client relations.
Drawbacks of 2D
Historically, one of the most challenging aspects of design and engineering has been developing the ability to conceptualize a 3D image based on the traditional 2D orthogonal plan and elevation drawings on paper. Isometric depictions, although certainly useful, are both time-consuming to create and extremely difficult to scale properly. The civil, mechanical and manufacturing engineers of previous generations knew this all too well, devoting many hours of double-checks and redraws to avoid one of the banes of every engineer's soul: interference.
Interference is second only to failure when one speaks to the negative consequences of mistakes made on the front end. Successful engineers and designers cannot afford to wait until fabrication or install time to find out if their drawings depict a condition that cannot exist in the real world. For the sake of safety and productivity, there has to be due diligence from the very inception of the project. These are the challenges that persist in a 2D world.
How can 3D modeling address these challenges and ultimately ensure success?
Looking Back: Roots of 3D
The introduction of computer-aided design (CAD) revolutionized the field, starting in 1963 with MIT's SKETCHPAD. This was the world's first practical graphical user interface (GUI), an indispensable feature of modern CAD. Not only did this new digital medium ring in unprecedented accuracy and speed, it also allowed for limitless, flawless reproduction and even the instantaneous transmission of drawings over standard telephone lines. It is interesting to note that the D in CAD originally stood for drafting, as this technology was originally seen as merely a way to replace the draftsman's table, offering no real contribution to the design itself.
Much of that changed in 1982 with the introduction of Romulus, the first commercial solids modeling kernel designed for straightforward integration into existing 2D CAD suites of the time. These advances allowed all engineering and architectural firms access to the productivity-enhancing tools that previously had been available only to extremely high-end companies and government agencies.
Although this 3D technology became readily available, the engineering field was slow to adopt it, historically. There were several reasons for this hesitance, not the least of which was the fact that the amount of computing power required to run these programs exceeded the hardware capabilities of most offices. This is no longer the case, of course, as processor speed has increased exponentially while becoming vastly more affordable. It is therefore not surprising to see 3D modeling becoming an increasingly dominant feature in today's drawing packages.
Busting 3D Myths
Today, other factors impede 3D adoption, many of them unfounded. One common misconception is that 3D modeling is time-consuming to learn and use and will add unnecessary cost to a project. Many believe that this "extra step" is overkill. Both notions are false for many reasons. The reality is that 3D modeling is fast -- it can save you time and money -- and practical.
3D models can have any level of sophistication -- from the simple polygonal faces of the B-Rep (boundary representation) block model all the way to a hyperrealistic structural assembly with simulated material properties assigned to it. Granted, the latter is indeed time-consuming to produce and requires a highly trained engineer or CAD operator, but the former is surprisingly easy to generate and requires minimal additional training beyond traditional 2D design skills.
In fact, a first step toward developing a 3D skill set is learning just three simple CAD commands: Extrude, Revolve, and Rotate.
- Extrude allows you to immediately add thickness to any continuous 2D geometric line.
- Revolve lets you revolve any shape about an arbitrary axis, much like forming on a lathe.
- Rotate lets you spin the model on any axis to observe it from all angles.
This explanation is, of course, simplified -- there is much more to the learning process. My point is that, in basic terms, the transition from 2D to 3D does not involve the major paradigm shift that many fear. For experienced operators, just a couple hours spent playing with these concepts will begin conditioning the user to think about CAD in a whole new way. After a few weeks, these skills start to become intuitive.
Benefits of 3D
In engineering, as a system design increases in complexity, so does the likelihood of interference. This interference risk applies to relative proximity of new to existing equipment and structures as well as to other new items. Only so much spatial information can be gathered from plan and elevation views and, as previously noted, isometric depictions are typically meant for schematic representation and are not useful for scale and real-world installation.
On the other hand, in 3D modeling, you create a single master model. Each part of the model exists as a separate entity, and is located at a unique coordinate in the xyz-plane. Each part occupies simulated space that cannot simultaneously be occupied by another component. A 3D model of a system and its surrounding environment enables quick identification of problem areas because you can easily view all parts and their neighboring interfaces from every conceivable angle.
3D master models have another benefit. In 2D, a single correction typically requires changing multiple drawing depictions, increasing the likelihood of error. In the 3D master model, orthogonal depictions of systems are not themselves drawn -- they are merely window views of the master model. You typically modify one model one time. From there, all associated views will automatically self-correct. Changes and corrections become much easier and more accurate.
In a 3D master, one correct model equals four error-free representations.
The potential benefit of 3D modeling becomes clear when you consider these issues. Depending on the project requirements, and your time constraints, you will determine the sophistication level of the model and its component parts up front. For example, would there be a benefit in depicting building columns as true W beams, or will an extruded I shape suffice? One needs only to determine the useful level of detail that should be built into the system model in general, and the individual components in particular.
Better Presentations, Happier Clients
Adopting 3D modeling can improve client relations as well. Project design review meetings usually involve many people from different specialties, and only some of them will be intimately familiar with your project. Many attendees will not come from a technical discipline. Projecting an image on to a conference room screen is always helpful to your presentation, but only if the audience understands it. Trying to explain a design to a senior-level, minimally familiar meeting participant using 2D plan, elevation, and detail drawings is usually a daunting task.
Presenting a fully rendered 3D model, on the other hand, provides a level of clarity to your customer that you simply cannot deliver with 2D. Zooming, panning, and rotating your designs for the group in real time allows for quick understanding and keeps all participants interested. The customer will leave the meeting informed and impressed.
Make the Move
There is nothing to fear about 3D modeling. It's not as complex as you think, nor is it the resource hog that many believe it to be. Managers, talk to your engineers and designers about beginning the transition. Look into introductory seminars or even online tutorials. Try to find a current or future project where a small, simple 3D depiction would be helpful and start from there.
3D is, and will continue to be, a vital part of any progressive engineering firm that aims to remain successful as we continue into the 21st century.
Autodesk Technical Evangelist Lynn Allen guides you through a different AutoCAD feature in every edition of her popular "Circles and Lines" tutorial series. For even more AutoCAD how-to, check out Lynn's quick tips in the Cadalyst Video Gallery. Subscribe to Cadalyst's free Tips & Tools Weekly e-newsletter and we'll notify you every time a new video tip is published. All exclusively from Cadalyst!