Is 2D Drawing Doomed? (MCAD Modeling Column)31 Aug, 2008 By: IDSA ,Mike Hudspeth
On the contrary, drafting still has a role in the world of more accurate 3D modeling.
During my last few semesters of high school, I stressed out about what I would do for a living. My mother wanted me to be a doctor — she even named me Michael David so I would be an M.D. from the start. Unfortunately, I didn't really want to be a doctor, but I had to do something. I wanted a job that would always be in demand. I looked hard and settled on drafting. Everything had to be designed, I reasoned, so there would always be a need for someone to document the design. I would be a mechanical draftsman, I concluded, thus fulfilling my mother's wish for me to be an M.D.
I have since moved on to other titles, and my job today is very different than the jobs I held in those early years. For me, the changes in my professional life were mostly out of necessity. But what about all the professionals today who create 2D drawings and depend on that skill for income? Some say that 2D drawing is becoming obsolete. I have to ask: Is it really?
In the good old days, if you wanted to create a product of any kind you sat down at a drawing board and sketched it. Next, you cleaned up your 2D drawings and added dimensions. Finally, you sent a large rolled up or folded piece of paper to your machine shop or builder. One of the things you had to worry about was a clumsy layout. On paper, if you began too close to an edge and had to add another view, you were out of luck; you ran out of room. It's embarrassing how many times I had to start over and trace something I had already done. And when you added notes, you could run into the same problem again. A drawing had only so much room, and once you started, you were committed. These problems were fixed for the most part when we left the drawing board and went to CAD. We could move things around to our heart's content until we had what we wanted.
One problem persisted, however.
I have known a lot of drafters in my career who were very talented organizers. (You really need that ability to do the job properly.) But one thing I was surprised to learn was that drafters aren't always artists. I worked with and saw the work of an amazing number of people who had no art skills whatsoever. Their drawings were barely readable. They just couldn't visualize in 3D. Elevations were questionable, and isometric views were a mess. They had everything dimensioned correctly, but very often the view wasn't depicted correctly. Even with a CAD system, 2D drafting is hit or miss. No matter how you shake it, you are still limited in 2D by what a drafter can visualize.
How's that Different?
When you are working in 3D, you are no longer limited by inability to visualize. Actually, creating drawings in a 3D system sounds pretty similar to what we have always done. In the modern 3D world, we still sketch. We can even sketch the same way we did in 2D, but our designs don't have to stay in 2D. We can scan our sketches and build 3D models directly from them, matching the curves we like with great precision. I guess the biggest difference between 2D and 3D is that we no longer try to depict what something will look like from certain angles. What we're doing now is actually — or virtually — building a part. We don't have to figure it out or try to see what it'll look like — we can just rotate it and see. There's no real art to it. 3D modeling is a better method — and a more consistently accurate one. It takes the guesswork out of the job.
We still create 2D drawings, even in 3D systems. In most systems, all you do is add your model — be it a part or an assembly, a machine or a house — to the drawing and then place other orthographic views around it (figure 1). The modeling system takes care of depicting what the model will look like in each view. Some systems even will use a standard layout with certain built-in specified views. One, two, three, and you're done. How easy can it be? After you've finished your 3D model, making a 2D drawing takes almost no time at all. Of course, you still must add your dimensions. But some systems can even inherit those from your modeling sketches. Creating 2D drawings is so easy, in fact, that I have heard some companies say that the days of drafters are coming to an end. They say that engineers and designers will be creating their own drawings.
Figure 1. It has never been so easy to create a 2D drawing. Just pick your model and place it. After the first view is in place, the rest are a cinch.
I have to question the logic of this thinking. The fact is, drafters are trained to know drawing standards and can present work in ways that most people will understand. Engineers are trained in many areas but seldom have more than a semester of drafting education. Besides, engineers are paid more than drafters. It makes more business sense to move drafting work to lesser-paid people who have more specific training for the job.
What's Going On?
We still create 2D drawings, but their function has changed. When I was fresh out of college, drawings were necessary for building not only the parts but the tools to make the parts. The model shop relied on my 2D drawings. That's not necessary in today's world, or even preferred. Nowadays, many companies cut steel by using their wonderfully accurate 3D models. The modern machine shop can take a 3D model file and pass it into its computer-aided manufacturing (CAM) program to tell its tools what to do (figure 2). These systems work directly from the 3D geometry. They are limited only by the size of their cutters.
Figure 2. CAM is a great thing indeed. There is no more accurate way to build a physical model. Modern CAM programs take a 3D model and calculate the path its tools must follow to machine a part.
Rapid prototyping (RP) is a 3D model application that bypasses the need for drawings (figure 3). In fact, except for some finishing work — and even that is getting less and less necessary — you don't even need tools for RP. Some RP machines tout resolutions on the order of 16 micrometers.
Figure 3. Rapid prototyping is the most exciting technology in the manufacturing world. With it, you can turn a virtual part into a real-life 3D prototype. Drawings and tooling are unnecessary. If a feature is in the digital model, it'll be in the RP part.
Lastly, there is simulation (figure 4). It used to be that you drew layouts so you could show the complete range of motion of the parts in your design. Now, you build the parts, put them in an assembly, then push or pull them around. If you've properly constrained them, they will act like the real parts. It's actually fun to watch.
Figure 4. If created properly, simulated assemblies will perform just as you would expect real objects to do.
Answers and Perspective
So how do we use 2D drawings nowadays? At the risk of oversimplifying the answer, I would conclude that 2D drawings today are used mostly for inspection. You have to make sure the parts your vendor hands you are within specification. To fully use the 3D models we've spent so much time and effort creating, it only makes sense that we would keep everything in the digital realm until the very last stage of production — when parts pop out of the factory. There's also history. If the government audits you, it's nice to have the drawings required. But in all likelihood, 2D drawing for specification is probably doomed — like so many other human activities. We have to grow and mature. It's natural. I prefer to think that 2D drawings will live on — but in new ways.