Make: Trigonometry

Chapter 9. Ellipses and Circles

3D Printable models used in this chapter

See Chapter 2 for directions on where and how to download these models.

• conic_sections_set.scad
  • This model slices a cone to produce all the conic sections.

• ellipse_slider.scad
  • This model creates an ellipse given major and minor axes, with holes at the focus and a slider around the outside.
• You will also need:
  • Two pushpins
  • A piece of foam core or thick cardboard
  • A piece of thin and not stretchy cord, like sewing thread, about a foot
  • Elastic cord. We used 0.8 mm elastic cord, also called beading thread or crafting cord. You will need about 1 foot per model.
  • If you want to make a Play-Doh alternative cone:
    • 8 ounces Play-Doh or other modeling clay
    • Unwaxed dental ...