Design happens in your head

Design Happens in Your Head

Different kinds of design happen differently. Mechanisms can be difficult. But so can flexible parts, and complex shapes. The ideas for these things have to come from somewhere. Rarely does a design just pop up on the screen without having existed somewhere else previously. I’ve written previously about the differences between engineering, design and modeling. Sometimes we treat all of these as if they are one and the same, but they aren’t.

We’ve already established that “modeling” is what happens on the computer. It takes an idea from another source, a sketch or 2D rendering, a physical model, anywhere, and creates the exact shape and adds all the functional details using computer software. In modeling, you make a digital prototype, or a mathematical model which can be used for analysis, post processing, or manufacturing. Modeling is not design.

Engineering is using calculation to predict how a part will work, and then changing the part to perform in a particular way. The process of engineering always forces you through a design phase. I usually think of it as a cycle of analytical problem solving followed by creative problem solving. So in this way, I believe that engineering is both analytical and creative. It has to be. Still, engineering includes design but it is not synonymous with design.

Design happens in your head. CAD vendors talk like they invented design, they want you to believe that their tool does the design for you to some extent. But none of this is true. Design happens in your head, not on the computer screen. What you are doing on the screen is documenting what’s in your head. I know it seems quaint and old-fashioned to use something so dirty and organic as your own head. I mean, a plastic and microelectronic device is so much more sterile than to even metaphorically get your hands dirty by using your head. Still, Design happens in your Head.

Change Happens in Your Head

Once you have conceived of how to do something in your head, only then can you get it down on paper, or into the computer. Let’s think about sketching on paper for a second. Sketching a mechanism or shape or series of shapes on paper is just an imperfect translation from the chimerical mental image in your head which is so easy to change, just by thinking it. The scrawled image on paper is less easy to change – either scrawl new darker lines or erase them and make new ones. Still, the change is relatively easy.\n\nNow think about making that kind of change that you just made on paper in SolidWorks. Yeah, sure, it works like the demos if you design things that you can practice like the demo jocks practice. But things in the real world aren’t like that, even in machine design applications. Parametric modeling is tough, it really is. We talk a lot about “design intent”, which I prefer to call “design for change”. Not even talking about making specific changes to a particular model, but just talking changes in general, “design for change” means that right up front you have to determine how the model will react to change. For example, design for change means saying something like “This row of holes always remains in line and is referenced from that edge.” Later if you want to pull a hole out of the row, not only do you have to make a change to the model, but you also have to make a change to the “Design for Change” scheme.

Some of the parts I have been working on lately are shaped in such a way that identifying individual features is not always easy. This makes “design for change” almost impossible. Combine that kind of challenge with short comings of the software such as losing references or worse yet confusing references when even the simplest change is made, along with all the other unpredictabilities that you run into on the fringes, and you can be cursing parametrics with little provocation. So, making changes is maybe not so easy as it is in the practiced scripted demos.

Documentation Happens on the Screen

So. Design happens in your head. Documentation and the excruciating technical detail of modeling happens on the screen. It sounds so mundane, but whether we make 2D prints or finish at the assembly level, SolidWorks work is all about documenting the design that’s in your head, and then getting it to change predictably.

That said, what would you do to make the computer a better design tool – meaning that you can get the idea out of your head and into a form that other folks can see quickly? Would you draw with a stylus on the screen? Maybe draw with your fingers? Using a 3D stylus with tactile feedback? Do it like Tom Cruise in Minority Report? Is parametric design really all it’s cracked up to be?