Modeling in 3 dimensions: utility knife

Modeling in 3 dimensions: utility knife

The humble utility knife has been around as a tool for a many years.  But it's not the most well designed tool in the toolbox.  You can do better.

Before you get into the guts of this project, I want you to go up to the fifth floor for a couple minutes.  Have Marie open up the "Measuring Humans" job for you.

Once you've read through that, you're ready to start thinking about this job.

Utility Knives

Now that you know a bit about ergonomics, let's consider those utilities knives I mentioned.  Here are a few examples of the many sorts that have been invented:

craftKnife3 craftKnife2 craftKnife1

You can see that there are a wide variety of shapes and forms used.  We also have some physical examples, in a box on the center shelf in our Workshop.  Take a few minutes to walk over and handle those.

  • Feel how much they weigh.
  • Hold them and imagine using them.
    • how would they feel in your hand as you started working?
    • how about after you'd been working for an hour?
  • What are the strengths and weaknesses of each of these types of knife (including the ones pictured here)?

Initial sketching

  1. First, pick three knives to make sketches on an A3 sheet of paper.  Do as detailed a job as you're capable of doing, including coloring (this is sketching practice, too. ;-)


Now, think about how you could make a more ergonomic utility knife.

  1. Look at your hand.  Examine it's parts.
  2. Look at your hand holding a utility knife.  How could the knife be better made to fit into a human hand?
  3. Remember that every human is a little different, too.  A knife that fits your hand perfectly probably won't fit my hand so perfectly.  How can you account for this?

Sketching again

  1. Now sketch out some ideas for how you could improve the utility knife.
  2. Once you have an idea sketched, put it (mentally) aside and come up with another idea for how you could change existing knives to be more ergonomic.
  3. Do this again, so you have 3 different ideas to choose from.  Sketch them clearly and annotate (make notes) as you need in order to fully capture your idea on paper.

Once you've done that, you're ready for the next phase.

From your 3 possible designs, I'd like you to select one that you'd like to model.  Outline it from 3 sides: top, side view, and end or front view.  These should make it possible to build a 3d model of your design in blue foam.

Here's a video of how the process happens.  (In case it doesn't work, the link to the youtube version.)  It's long, so I'd recommend watching it at double-speed. There aren't any words, just a demo to watch; he covers the entire project from sketch to finished model.

If you'd prefer to listen to a walk-through of the basic tools and process of foam modeling, Henry Lin has kindly made that available too.  (Youtube link)

When you feel comfortable that you know the process, you're ready to head into building your craft knife model.  Take your sketches and gather some blue foam, the hot wire cutter, large utility knife, small utility knife, metal ruler, cutting mat, and sanding sponge and get to work.  If you're not sure where to get any of these items, see Number One.

You don't need to paint your model, but if you'd like to, we do have spray paint.  See Number One for the details.  When your model is completed, turn it in to Number One for a review and discussion (and we'd like to display it for a while, too!).

Hot dog, Visitor!  You're really getting into it, now.  If you haven't yet, you might want to try cardboard modeling next.

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