In order to produce 3D printer compatible objects, it is important to understand its limits. I like to think of a 3D printer as a spaghetti machine. It carefully stacks noodles on top of each other, and if there isn't enough noodle to stack on, it droops. The following three design elements can be implemented to help prevent drooping and will allow you to successfully print overhangs.

  1. The 45° Rule: In general, 3D printers are restricted to overhangs that are under 45°. This allows for enough material to be present under the new extrusion and helps to prevent drooping.
  2. Peaked circles: If you need to create a circular feature that is perpendicular to the build platform, taper the top of the circle with two tangential lines so that the 45° rule is not broken.
  3. Support structure: Many slicing engines will detect overhangs and can generate a brittle support structure that provides support for overhangs over 45°. This is a nice feature to use, especially when overhangs are unavoidable, but usually uses a ton of filament in the process.

Check out Makerbot Thingiverse for models and design ideas for your next project. Their friendly community has a ton of 3D printer compatible models to share.
This guide was first published on Aug 05, 2013. It was last updated on Aug 05, 2013.
This page (Designing for the printer) was last updated on Oct 24, 2020.