Tuan Makes Almost Anything


Modeling a Final Project: Ferret Puzzle Feeder

I think I took more time actually thinking of an idea than CAD'ing the design. At some point during the week, I had read somewhere how cats and similar pets enjoy having to work to get their food. Additionally, over the summer I became infatuated with the idea of owning a pet ferret (in an alternate universe where I have the time and money) and someone in my dorm owns a "short cat that is totally not a ferret" (which I got to play with!!!). If I make this I will test it on that "short cat that is totally not a ferret".

  • Technology: Antimony and OnShape
  • Week: 0

It took me a long while to figure out an idea that would combine all of the elements of the class. I was inspired by my burning desire to own a pet ferret, in addition to the basic idea behind the self-playing chess board, which I thought was a project from a past year (I think was misremembering this one).

Preliminary design sketchup.

The premise is that the body is a square maze. Within the maze is a cup that ferret food can be put into. There are buttons on all four sides of the maze which will move the cup around within the maze, and the only way for the ferret to access the delicious food within is to successfully navigate the cup through the maze to an opening in the center. It would be a fun mechanism for both feeding the feret and playing with the ferret.

Next, I'll talk a bit about my previous experience with modeling software. In high school, I started using paint.net and then later GIMP as image processing tools to make funny pictures with my friends. You can see my beautiful works here . Then in college, I started learning Vectorworks for lighting design purposes and SketchUp to CAD designs for my loft.

I ultimately chose to CAD the design in Antimony and OnShape, because I wanted to compare Antimony with a more traditional CAD software, and I felt that OnShape was the best CAD software to learn after SketchUp. Plus, I also thought Fusion 360 was only for windows, like most powerful CAD software is.

Antimony: sucking every last bit of my soul

First comments about Antimony: I really liked it, because I naturally think geometrically, but it's haaaard. Since I can't draw something and adjust distances later, it was very useful to have a drawing on graph paper. Specifically, I had to count the squares in my notebook to get the correct centers for the walls of the maze, which took quite a bit of time. I especially liked how I could define a set of parameters (like the radiuses for the cups or the height of the box) and change the entire design by changing the parameters. I played a lot with the height of the box to see what looked best, so I'm glad I designed it in Antimony first, even though it took much longer in Antimony :/

I'm starting to really like OnShape

ONSHAPE IS SO MUCH EASIER!!! It took me so much longer to CAD the same design in Antimony, because I had to be more explicit about many of the components. For one, to make the cup shape in Antimony, I had to use a series of CSG nodes with two cylinders and a sphere whose dimensions depend on a set of parameters. In OnShape, I just made a cylinder and used the "hole" tool to drill a hole into it. It was no longer as nice and polished as the Antimony design, but it was easier. Similarly, the button design took much less time in OnShape, because there is a "fillet" tool to round corners. In Antimony, I instead had to plop a specially parameterized torus between two cylinders. And talking to the MechE's in the class, more powerful CAD softwares come with so many other convenient tools as well.

Case in point: I really REALLY like OnShape. It's intuitive on a different level than Antimony, in that the tools it has align with the methods of actually fabricating the material (you start with a base shape and then modify it with a tool). However, in the immediate future parametric programming will probably be more important than ease of use :(

Overall, I'd compare traditional CAD software and Antimony to Microsoft Word and LaTeX. Traditional CAD is just easier to pump designs out as opposed to Antimony, where you have to specify everything, but you have more power in designing exactly what you want (plus you get the power of copy and paste!).

Here is the Antimony file and here is the link to the OnShape design.