Easter 3D Print (and Splitting a 3D Model in Half)

Holidays are a good excuse to find something whimsical to 3D print. I found this pair of egg legs over on Thingiverse and chuckled. The legs are pose-able and hold an egg. Wife sketched an Humpty Dumpty on an egg and suggested I shoot the model in the garden. He can stand (above) or sit (below).

When I loaded up the model, I discovered the pieces would be difficult to print. Turns out the original designer is a grad student at MIT Media Lab and has access to a fancy industrial grade fabricator. On hobby printers, 3D objects are easiest to print when they have one flat face to serve as a base. For example, pyramids are easy to print and good for testing a printer setup. Otherwise, when an object has a part that hangs in mid air, the printing software can insert extra material for support. Sometimes though, some objects are just unprintable.

This model has 5 pieces: feet, lower legs, left & right upper legs, and a torso. The feet were easy. The lower legs printed OK with support. I rotated the upper legs 90 degrees and printed them with support. The "egg holding torso" print, however, failed miserably. To solve the problem, I was able to make my own flat face on the object by slicing it in half, printing the two halves, and super-gluing them together.

Surprisingly, there are few solutions for cutting 3D model objects in half to be googled-up. I ended up using Meshmixer, with which I've had varying success in the past. This time, however, it worked perfectly. Import the STL file and select "plane cut" under the "edit" menu. The default plane was oriented exactly along the major axes, splitting the part in half easily.

Print two, glue, build, pose, photograph, write a blog post. Happy Easter.