Why the transition from 2D to 3D is taking forever

For as long as I can remember, sophisticated 3D CAD systems have been on the verge of fully replacing the supposedly inefficient 2D CAD systems. For years it has been considered just a matter of time before the obvious advantages of 3D systems would push traditional 2D systems out of the market, all with great advantages for designers, companies, and users.

years have passed and 2D CAD systems are still around

Years have passed and 2D CAD systems are still around. We are now approaching the year 2007 and one of the most successful CAD systems is AutoCAD LT, a popular 2D system. If the 3D is so great, why all those people are still using a 2D CAD system?

In order to find an answer, let's ignore the few design contexts intrinsically 2D, where the benefits of 3D are not so obvious. Let's also exclude from our discussion those users that are  too rigid or conservative to switch to a new technology, regardless of the advantages. We still left with huge number of 2D users.

Today the cost of a state-of-the-art 3D parametric, feature-based CAD system is comparable with the cost of AutoCAD LT. What's keep those designers and their companies from switching to a 3D?

In order to explain my opinion I'll need an example.
Let's assume we need to design a simple L-bracket part. We can draw a couple of orthogonal views with a 2D system, add a bunch of dimensions and notes, and it's done. Similarly, with a 3D system, we can create a simple profile and extrude it to generate a 3D shape. So at this stage, there is no significant difference between 2D and 3D systems. The advantages of the 3D solution will become evident only if and when we reuse the 3D model in the following phases of the design and manufacturing process, such as when will have to go back to our computer to change the size or shape of our L-bracket. Designers know it very well: it's just a matter of time, someone will always want a change.

For the purpose of this example let's assume we are not a very skilled CAD user, or we are just thinking about our next vacation. Because of that, our sequence of commands to generate the CAD model of the L-bracket would be not optimal. If our system is a 2D system, nobody will ever know how we completed the design. A 2D model is just a collection of simple geometric entities and some text. As long as the drawing makes sense, it doesn't matter how we got it.

Based on our hypothetical limited skills, if we were using a 3D system instead of a 2D, the situation would have been completely different. On one side of the screen the "history tree" will reveal to everybody all our mistakes. Our (supposedly) poor skill would become evident the same moment we need to go back to our 3D model and change some dimension or add new features and details.

a poorly modeled 3D model is virtually unmodifiable

In every 3D CAD system, parametric models created by a "well designed" sequences of operations can support a wide range of dimensional modifications with predictable and consistent results. A well-crafted 3D model can become the archetype for a large group of products. The opposite is also true: a poorly modeled 3D model is virtually unmodifiable. Every tentative to change a critical dimension or to add more details will cause the failure of the model regeneration.

Most of the parts designed every day by CAD users are by far more complex than a simple L-bracket. The higher the complexity of the part, the more critical is the 3D modeling sequence of commands, and more challenging is the task for a 3D CAD operator.

With a 2D CAD system the situation is different. The design process can be even more difficult, because it must be done without the support of a 3D model, but the modeling phase (2D drafting, in this case) is a lot simpler than the corresponding 3D modeling phase. The effort to create a 2D model grows (approximately) linearly with the complexity of the part we intend to design, while the effort to create a 3D model grows with the square of the part complexity and size.

When we look at the big picture of the design and manufacturing process, the initial investment in building a 3D model will pay off with huge interest. (For more on the benefits of transitioning to a 3D system, check out the recent Cadalyst article.) A 2D solution can easily perceived as optimal only if you limit your analysis to the design phase. Transforming ideas into products is a long and complex process, and creating a 2D or 3D model is just one of the first steps.

I welcome your comments on this matter.

Franco Folini

Post Scriptum: You can find a continuation of this discussion on my more recent post: Frederick W. Taylor and 3D Technology.

Comments

[Norman Campbell]

As a furniture and hardware manufacturer, specializing in both custom and stock work, I really hope 3D never comes to pass as an industry standard. There's so many things both software designers and architects/designers still need to work on. As for the arch/designers, furniture is measured in inches, never, ever, ever feet, especialy if we [metal workers] need to coordinate w/ wood workers.
As for software designers, better means of evenly dividing up screw spacing and other such mathematical stuff, I mean I know it's in there, but I need to be a generalist to run my bussiness and really don't have time to learn mathematical expressions, Besides if I was really all that good at math I would work on Wall Street. Can they say intuitive, off course they can. Also how about a ruler on top and side of the drawing window as in painting programs, or better yet a little graduated square you could move around your drawing to measure and layout stuff as you do in real life, I find it hard to believe no one has come up with the virtual drafting arm. We use Ashlar-Vellum Graphite so I don't know if this exists in AutocadLT.
Oh yeah, and how about having a computer station at every machine, and every non college educated worker I hire learning to discern a 3D drawing to do their job. A lot of my drafting work is involved in breaking down large jobs and simplifying things so my workers don't make mistakes. I'm not looking forward to doing that with someone elses fancy 3D drawing.
Also, we recieve a lot of jobs from said architects/designers in sketch form and we do the drafting, obviously a lot of people in the industry find it either difficult or time consuming to do Cad as it is.
And don't even think about designing scrolls with a CAD, gracefull curves don't exist with my skills. These are the things that are on the top of my head right now, I'm sure during the day I will think of enough more to fill a small training manual.

[Donald Beams]

Food for thought from the Ice Age. I tiptoed into the Computer Aided Design age about 1992 after years of resistance, having noted that most of the early computer drawings that crossed my desk were virtually unreadable at first, (had no one ever told these folks about the virtues of line width or weight?) Additionally, I justified my resistance by the arrogant, technologically ignorant (although pretty much true) observation that most of the work product depicted was unimaginative unadulterated crap from a design viewpoint.

I cruised along for years with pencil in hand, confident that computers only allowed the incompetant to churn out crap at ever- enhanced speeds. What a boon to mankind that is!

Then I got the chance to play with a Mac loaded with ClarisDraw. With no instruction and no manual, I completed an orthographic drawing of a wood, metal & glass cocktail table in a couple hours, in full color with excellent rendition of gradients depicting curved surfaces and materials. This was accomplished by the "I wonder what this tool can do" educational method. The learning curve was amazing. Within two weeks I learned 95% of what could be accomplished with this wonderful tool and have never picked up a pencil, even to sketch, since then.

My customers, mainly interior designers, loved the full-color presentation version of the drawings that they could sell from, and that neither of us could have afforded if hand-colored, and my vendors loved the production drawings, which were the original minus color with more dimensions and details added. I loved the capability to depict the same piece in mahogany instead of maple with about 5 minutes of work or to convert a presentation drawing to a production drawing in about 30 minutes or less.

Thoughts of expanding my knowledge and presentation capabilities led me to investigate other CAD systems and operating systems. Oy... Working the same ClarisDraw program on my wife's PC led me to the inescapable conclusion that PCs were an awkward, slow, counterintuitive pain-in-the ass, appealing to masochistic technophiles who love to brag or bitch about their toys in a worldly "I'm better than you" fashion. These guys would look at prints of my presentation drawings and ask with real excitement what software I used to produce them. When I told them it was ClarisDraw their excitment would intantly turn to a sort of disdain and they tended to turn up their noses and wander off shaking their heads in that wonderful superior AutoCAD student way. Or perhaps it was chagrin that they had wasted many thousands of dollars and hundreds of educational hours and still couldn't produce a decent design or a realistic depiction of same. C'est la Vie.

16 years later I still sketch, do presentaion and production drawings, design houses and produce multi-layered construction/permit sets in the totally out-dated and unsupported Clarisdraw because I can do it incredibly fast and there is no discernable difference in quality from the work product from obviously "superior" CAD systems.

Still I yearn (slightly) to update myself into the 21st century because it just SEEMS LIKE I SHOULD. Instant 3-D conversion would be nice, although in 15 years, I encountered only a couple of "Graphically Dyslexic" souls who could not mentally merge a front, side & top view of something into a perspective view in their head. I usually have a completed design picture in my head before sitting at the keyboard and am simply reversing the process in order to depict the product for the customer. Software is less a "Design" tool for me than it is a "Depiction" tool. I have almost never heard the dreaded post-delivery adenoidal phrase " I didn't know it was going to look like THa-at." Maybe I was just lucky...

At any rate, I am excited about the possibility of purchasing Vectorworks this year. An architect friend gave me a brief demonstration and I noticed that most of the tools and the graphic interface have an uncanny resemblance to good ol' ClarisDraw. Is this an accident? Who knows the answer to this question, cause my curiosity is getting the better of me.

[Reinaldo Martínez]

3D CAD is a great tool to show the non-especialist (customer) what a design will look like in the end. But we architects still have to prepare a great deal of paperwork for permits and construction docs in 2D. No engineering office that I know of will accept a CD with lovely, costly, time consuming walkthroughs, flyarounds and photorealistic renderings for permit purposes. The reason is simple, you would need highly especialized staff to revise, inspect andreview such virtual docs. Instead you can use any skilled AA to check a whole pack of paper drafted 2D blueprints.

Another good reason is that not all 3D CAD packages can easily turn 3d models into 2d bluprints and we still need the latter. I can't visualize a contractor sitting on a bunch of bricks in a concrete splashed site with a $2,000 laptop checking the stair threads on the screen to instruct the bricklayer. Can you?

Regards

[Franco Folini]

Mike, I agree with you. Many CAD companies are investing mainly in 3D systems with a minimal development on their 2D systems. IMHO, there still space for huge improvements on current 2D CAD systems to speed up the drafting process and to make designer’s life easier. On the other hand, the price of the average 2D system is now so low, that is becoming more and more difficult to justify any further development and investment.

[MIKE]

At the end of the day, we still have to make 2d drawings to give to the floor, even if we have 3d solids for cutter paths (not enough $250 000 CNC machines, and a lot of $2 000 bridgeports). On top of that we have Software companies working against us and developing 3D GD&T, and fancy PLM solutions instead of improving the drafting commands that would let me produce a 2d drawing faster from that solid. Catia is a great software, but good luck sketching something up fast just to show the customer. I can do a better (and 10 times faster) job in Cadkey.

Even though, 2d drawings are getting easier and easier to create from solids, it's still not at a point where it's negligible. It's almost like doing the work twice. I'm a Mold designer, and I have patterns saved for all the components that we usually get. Lot of business do similar things. It's not like we do the whole thing from scratch, line by line.

Maybe I’m wrong, but I just can’t see all those architects, doing basic house plans, drawing bricks and shingles in 3d software, constraining all of it together and all that jazz.

I see the guys next to me (who do surfacing) struggle on how to do things (proper procedure) to get their parametric right so that it’s editable and simple, while concentrating half as much on how the darn thing is going to look at the end.