Author: gzumwalt, published on 2014-06-01

Click this button to get the 3D model


Hand operated animation of an immovable object and an almost unstoppable force. Makes a great conversational piece as a bookend, and printing the figurine in glow in the dark filament produces mesmerizing nighttime results.

You’ll need perseverance to assemble this thing as there are numerous parts.

Slow motion video of this thing is here:

Video of the prototype (which is motorized) is here: This is the prototype, the hand operated version is the final design. If anyone is interested in the motorized version, I’ll upload the motorized files.

This thing was inspired by the “Disney Computation Designs of Mechanical Characters” video here: A nice study of fulcrums, gears, etc. Wonderful work. I wrote my own software to simulate the interactions of the various parts.

Designed using my own software and Sketchup 8, and printed in PLA on a Makerbot Replicator 2 using Makerware


Carefully study “Assembly.skp”. Note that the .skp file should be used as an assembly diagram and not be used to print parts as the parts in the .skp file may not be the final parts as found in the .stl files.

Print all PLA parts from the .stl files.

Test fit and trim, file, sand, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces.
Assemble as per “Assembly.skp”.

Lubricate moving surfaces with light machine oil.

Some cyanoacrylate may be helpful in holding certain parts in place.

Comment if questions.

Hope you like it!

License: Attribution – Non-Commercial – Share Alike