Unplugged: Projecting Geometry for Precision Cutting and Assembly – SCOPES-DF
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Lesson Details

Subjects
Engineering, Mathematics, Technology, Unplugged
Age Ranges
11-14, 14-18
Fab Tools
2D and 3D design software, Hand Tools, Digital projector
Standards
Fab-Safety.2, Fab-Modeling.2, Fab-Design.2, 8.G.A4, 7.G.A1, 7.G.A2, 5.G.B4, K.G.A3, K.G.B4, HSG.MG.A1, HSG.MG.A3
Author
Daniel Smithwick

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Author

Daniel Smithwick
Daniel Smithwick
Maker
I am the Product Manager (Master Fabricator status) for the SCOPES-DF project. I collaborate to build foundational and scalable digital fabrication knowledge for the next generation. I received a PhD from MIT for my dissertation on Physical Design Cognition and previously… Read More

Summary

In this lesson you’ll learn how to make complex and precise geometric assemblies – like the skateboard halfpipe seen here – without the need for a laser cutter. Inherent to this lesson is the development of an understanding of projective geometry. Particularly, this covers concepts such as geometric workplanes, scale, perpendicular and parallel, and tolerance. In addition, this lesson develops fine motor skills and patience.

 

This lesson was originally built as a 3 day hands-on project during the 2019 Constructing Modern Knowledge conference in NH, USA.

 

Here’s a link to collaborate on the original TinkerCAD Skatepark!

 

What You'll Need

  • No laser cutter needed!
  • Digital projector (or large format printer)
  • Computer and internet access
  • TinkerCAD (download here)
  • Fusion Slicer (download here) 
  • Foam-core or cardboard
  • Sharp cutting tools, such as X-Acto knife or box cutter
  • Pens or Sharpies
  • Rulers or cutting edges
  • Cutting mats

 

SAFETY FIRST! This lesson requires using precision cutting blades – such as an X-Acto Knife or similar box cutter – which are very sharp. Children should be supervised at all times while using such tools.

Lesson Materials

The Instructions

Create Your 3D Design

Use your favorite 3D modeling program - I like TinkerCAD because it's web-based and free - to create a solid 3D model of the object you'd like to make. I've created a whole skatepark in TinkerCAD simply by adding and subtracting geometric primitives together such as rectangular and triangular prisms and ellipsoids, Students can explore concepts of scale, transformation, and work-planes and world-planes using basic commands in the program. TinkerCAD is also an online community, so it is a nice way to introduce students to online profiles, file-sharing, and cloud-based computing.

Slice your 3D Design

TinkerCAD can export .stl file types (good for 3D printing too), which means you can take your digital work with you into different programs. In digital fabrication practices this importing/exporting - the transporting of files from one program to another - is often referred to as a 'workflow'. Now, export your geometry from TinkerCAD and import it into the program called Fusion Slicer. This program will automatically generate laser-cutter ready files (2D files) from your 3D geometry. It does this by projecting slices - or planes - through your model. These slices can be parallel to each other, perpendicular to each other, or even radially distributed in 3D space! The program then generates laser cutter cut sheets (vector files) with the individual parts laid flat, nested - or arranged compactly - and also labeled for easy assembly. Explore all the parameters on the left hand side of the interface to adjust the slices for your particular model.