A few weeks ago one of the folks over at SketchUp got in touch with me about making a new desk for their office space. There are already a few OpenDesks around the office, and quite a few of my Maker Benches as well. What was needed though was something that was a bit custom. I always jump at the chance to make something new and different. After a few emails back and forth I fired up SketchUp and did a few quick mockups. My first idea involved some galvanized pipes:
This model only took a few minutes to put together. It’s not a completely engineered model, but it was just enough to get the general design sense communicated. After some more iterations this is what we came up with:
It’s more than just a pretty picture too, it’s got all of the engineering details worked out. This is a ready to CNC mill model:
This model, like many other complex models in SketchUp is full of all kinds of fiddly bits like bolts, hardware, dowels, and detailed joinery. Usually when I build models of this complexity I start off simple and then as the details get ironed out I add in the engineering bits. Some basic modeling techniques were used in the concept model, and then some more advanced modeling was done to create the engineered model. However, I realized that one technique remained the same throughout: the use of components to maintain symmetry. Allow me to explain...
Put simply, a component is a bunch of geometry in SketchUp that you can reuse over and over again. If you edit one of the components, they all change.
This can be incredibly useful if you have tons of the same thing in your model; think of stair treads, balusters, tiles, or just about anything that requires you to have many copies of something. If you don’t know about components, go here to get all of the nerdy details about how they work.
I use components for models like this table a little bit differently; I use them to create symmetry. For this example, I’m going to show you how I would draw a tabletop. Let’s say you wanted a simple curved tabletop like this:
Most people would draw this shape using a technique like this:
There’s certainly nothing wrong with drawing this way, but I like to think/draw a bunch of steps ahead of where I am in drawings like this. First, I know at this stage that the tabletop is only for approval. Do they like the curve? Do they want it bigger... smaller... reversed? I’m not sure. I do know that it’s going to be symmetrical though. I also know that the legs and everything that attaches to it will be symmetrical too. So my approach is a little different. I’d only draw half of this top and make it a component:
Next I’d copy it using the move tool, and mirror it using the “flip along” command.
What you end up with is a table that’s made up of components that are mirrored. If you remember from earlier, whatever I do to one component gets mirrored to any other components in the model.
So let’s zoom back out and look at this table. Every part of this model that has symmetry is built in this way. I turned on hidden geometry in this view so that you can see your mirror lines.
I modeled this way from the very beginning before there was any engineering or heavy detail in this model. At the design stage it allowed me to easily change the shape while maintaining symmetry.
As the model got dialed in, I added every little bolt hole, piece of hardware, round-overs, and all of the other details. As I modeled, everything got mirrored to the other side. Not only does this save time, it drastically reduces the chance to make mistakes.
This technique can work for just about anything that has symmetry. Think of buildings, 3D prints, woodworking, metal-working, you name it. I bet if you look around your desk right now there are 10 things that have some kind of symmetry to them.
Moral of the story: Model smarter, not harder!