The right tool for the job: Why designing in 2D is still commonplace

However, despite ever improving graphics and more intuitive interfaces, designing in 2D is still common practice. But, it seems the argument has shifted slightly in recent years in that it is not so much a question of 2D vs. 3D anymore, but of how to make the best use of both. "There is still a need out there for 2D," says Steve Bedder, manufacturing technical engineer for the UK and Ireland at Autodesk. "You do get firms that rely on 2D for the mainstay, but even there they have invested in one or two licences of 3D. Of course, 2D is still king when it comes to manufacturing. For many that's ultimately the endgame." Producing 2D drawings from 3D models has been commonplace for years. But, using 2D design data to make 3D models is something that has been far less exploited or integrated. And despite numerous attempts, the design community still use 2D much more than some would have, or like, us to believe. Iain Lewis, principal technical sales specialist at PTC says: "There is, and will always be, scope for 2D design. Certain things just do not lend themselves to being designed in the world of 3D such as factory layout, electrical schematics, or process schematics; there is no way you will ever want to do that stuff in 3D." But it is not just niche areas where 2D is prevalent, conceptual design is often as much about finding and balancing numbers as it is about aesthetics and geometry. Sums need to be done in order to start finding real mechanical design data. And simple hand calculations, for example, are often easier to visualise and calculate around 2D sketches than on complex 3D models. The key here is being able to capture that data digitally and then using it as the foundation for a 3D model. As a result, many of the CAD giants are rolling out increasing, and more integrated, 2D capabilities to accompany the 3D design packages. "Autodesk's Digital Prototyping Solutions combine that need for both 2D and 3D," says Bedder. "Design engineers still use 2D tools within the Product Design Suite to do layouts and concept drawings; what we want to do is have the ability to reuse that 2D data for 3D design. "For example, wiring schematics in AutoCAD Electrical can be used in Autodesk Inventor, so the 3D layout and routing of the wire around a structure can be done at the design phase rather than having to let the guys on the shop floor work it out." PTC has also increased its 2D offerings with Creo, its PLM package. It has worked with various vehicle manufacturers that, from the outset, do a lot of development work in 2D. It says this is generally 2D layout work which can involve the pitch of the seats to calculating the wheel base to where the doors should be placed. Ian Pilkington, technical manager at PTC, says: "It is very easy to visualise and to collaborate on screen if you have a nice 2D section through a vehicle and you can move things around and check distances. Engineers relate to that a lot better than a complex 3D model. "We have developed a layout product to allow this 2D concepting to then drive the 3D design. You can effectively take a section through a product and build up from there. We call this 'Design Intent', which builds constraints in to the model and then that drives the 3D geometry afterwards." However, all this is not to dismiss the need and benefit of modern 3D CAD packages. For many aspects of the design process, 2D just does not cut the mustard. Many modern designs, from cars to computers, feature curvature that is just not possible to detail in 2D, it has to be 3D. Additionally, the packaging requirements of many modern electronic devices such as mobile phones or the iPad are too complicated to be attempted in 2D. Again, it needs to be in 3D. And 3D has itself become the currency in which engineers need to tender for business. Trying to become a supplier on many OEMs books requires 3D models, and often CGI rendered imagery to give presentations an edge over competitors. Pilkington says: "Having a full 3D representation of the part you are supplying is critical. You've not only got the calculations around weight, Centre of Gravity, stress and strain as well as the fact that if you are a supplier – certainly in many sectors – you will probably go out of business if you can't supply 3D geometry to an OEM." A general criticism in the past toward 3D CAD has been its over complexity and difficulty of use in terms of initial implementation, retraining, and also the time it takes to model what should be relatively straight forward and simple components. "All too often we find that design engineers are 80% CAD experts and 20% design engineer," says Bedder. "They constantly have to think about the tool that they are using rather than do the value added design work which is making the products more innovative." Many of the CAD companies have seen this as a key product driver; making their systems easier to use and more intuitive. "You don't want to have to think about construction geometry, datum planes, component libraries, and those kinds of things," says Bedder. "You want to solve the problems." Autodesk has been rolling out a host of Functional Design Tools to help speed up this process. These create fairly standardised geometry for parts and components based on inputs by the engineers. Bolted connections are a good example. To bolt two plates together, the design engineer would normally have to create two holes, go to a library and find the correct type of ISO fastener, then a corresponding washer and bolt. "In Inventor you say that you want to bold two plates together and you know that these two plates will be pulling apart from each other with a force of 2 tonnes," says Bedder. "Inventor will then say, based on that information, you need a nut and a bolt of this particular size with this particular washer and this particular nut. And you will need four of them." Although this doesn't make the decisions for the engineer, it does guide them along the correct path earlier in the design process. So the design engineer can make informed decisions much earlier on in the process. PTC also has gone to great lengths to ensure Creo has one of the most consistent and easy to use interfaces, which it says, has the shortest ramp up time to get people productive. It says the key is streamlining the whole design process and making it much more integrated. Pilkington says: "People understand that 2D is good as a concept tool, but when you are talking about the full definition of a product it needs to be designed with 3D, and the challenges are really around the rest of the process. "The biggest opportunity for PTC and our competitors is the streamlining of the whole design process; doing the concept work upfront, in either 2D or 3D, being able to deal with simulation issues, stress/strain, ergonomics, dealing with suppliers; that is really the real big challenge."