Animatronic C-3PO


Sr Member
In September 2018 I began a project to build an animatronic C-3PO. I'm going to post here to record my progress since then, an hopefully keep updates coming until it's finished. The goal is to have him operational for Star Wars Celebration Chicago in mid-April 2019, working as the greeter at the Droid Builders room. One stretch goal is to have him tell the story of the saga in Ewokese, as he does in ROTJ.

This will be a stationary animatronic with as much range of motion as I can achieve. My goal is to replicate the movement and degrees of freedom of the C-3PO animatronic in the Star Tours queue area in the Disney parks. So, anchored at the feet, with legs and pants that can pivot at the waist, torso movement front-back and side-side, full shoulder-arm-wrist-finger articulation, and neck/head motion. I want to program the motion to be as realistic as possible, and to truly convey the spirit of the character. Voice-over, background sound effects, and a lighted base are also part of the plan.

I’ve wanted my own protocol droid for decades, actually longer than I've wanted my own astromech droid (which I've had completed since 2005). Now’s the time. Also, I am too claustrophobic to even attempt it as a costume. Plus I could never achieve the perfection of Gordon Tarpley or Chris Bartlett or Simon Wilke. So, animatronic it is.

Project components:

3D Printed Body Part Shells
  • Head
  • Torso and Neck Ring
  • Shoulder Bells and Bearings
  • Arms
  • Pants
  • Legs
  • Feet/Shoes
  • Greeblies (some in machined brass)

Mechanical Subsystems
  • Neck motion (3DOF)
  • Shoulder motion (2DOF each)
  • Elbow motion (1DOF each)
  • Wrist motion (2DOF each)
  • Finger motion (5DOF each hand)
  • Waist motion (1DOF pivot)
  • Torso motion (2DOF)

Electronic Subsystems
  • Eye lighting
  • Audio system
  • Base lighting
  • Power control
  • Motion control
  • Show sequencing
  • Wire management

  • Fiberglass interior coat
  • Mount points
  • Priming
  • Sanding
  • Chroming
  • Weathering

Base and Frame

Transport Crate

I'll be posting updates as things happen. Here are some of the sketches from my project sketchbook where I try to work things out on paper before going to CAD or fabrication/prototypes:

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Sr Member
3D Printed Body Part Shells

I’m using Jesse Maricelli’s excellent models. They’re on Thingiverse: Jesse_M's Thingiverse Profile

For 3D printers, I have two Formbot T-Rex2's, a Creality CR-10S4, and a Monoprice Maker Select V1.

Up until Feb 2019 I've been printing everything with a .4mm nozzle. Now I'm looking at switching to .8mm nozzle and .8mm wall upon the advice of Gordon Tarpley and Tom Spina.

Using mainly Hatchbox PLA 1.75mm filament at 210/60.

Video of all three large printers running droid part files overnight (Nov 10 2018):
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Sr Member
3D Printed Body Part Shells - Feet/Shoes

Printing the first set of shoes (upgraded to a different pair later on), and cutting holes into foot soles for clearance around vertical aluminum extrusions (frame to be discussed in future posts):

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Sr Member
3D Printed Body Part Shells - Pants

After 60 hours printing the front, 12 hours on the leg rings, and a whopping 72 hours for the back half we have COMPLETED SPACE PANTS! SPACE PANTS! LOOK AT THEM! YES ! YES! YES! YES! (From the week of October 2-ish, 2018)

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Sr Member
3D Printed Body Part Shells - Hands

Right hand plate print complete. Next: print the fingers (From models by Gordon Tarpley) on or around Nov 10, 2018

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Sr Member
This is very exciting!
I wanted to say something about having to be careful in my excitement to not short-circuit... but anyway, this is looking awesome so far! Goldenrod does not get the love he deserves on the boards.


Sr Member
3D Printed Body Part Shells - Legs

Lower left calf pieces printed and test fitted (Sept 20, 2018)

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Plane-cutting the left thigh shell for printing. This produces a perfectly flat face for each part to rest on the print bed surface. (Sept 25, 2018)


The results of over 77 total hours of printing for the left thigh piece (Sept 27, 2018)

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Printing and gluing up the left knee assembly - this was the first round of leg printing before Jesse's new files were released (Sept 27, 2018)

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Sr Member
3D Printed Body Part Shells - More Legs

Re-printed the legs from Jesse's new files. To paraphrase Morrissey, “Every day is like leg day.” Feb 4-10 has been Left Leg Week. Feb 11-17 was Right Leg Week. After filling and sanding the seams will disappear.

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When a critical support tower fails halfway through a 48-hour print, you go full MacGyver to save it.



Sr Member
3D Printed Body Part Shells - Never Skip Leg Day

I am pleased to officially declare the end of Leg Week(s). Here I'm test fitting the legs and feet/shoes on the aluminum extrusion frame. The torso pivot mechanism has been removed for this photo. All of those seams will get sanded out and disappear under the primer coats.



Sr Member
Fiberglassing and finishing

The interior of each body shell part will get a layer or two of fiberglass mesh and resin for strength, and to allow for attachment points. Outer surface will get multiple coats of automotive filler-primer (2K / catalytic) and wet sanding for a gloss finish. Then a coat of hydrochrome for that shiny look.

Here's the first couple of layers of fiberglass mesh and resin on the inside surface of C-3PO’s front and back torso shells and one of the shoulder bells.

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Sr Member

The frame uses 4040 aluminum extrusion and connectors. It's good and solid, and allows for adjustment and attachment. Originally built it to be a 42" square base in September 2018.

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Later on in October 2018, I spent time cutting down the 40mm 80/20 aluminum extrusion base to get it below 28.5 inches so it will fit through most doorways. Planning ahead for April 2019 when this rig has to travel to Star Wars Celebration.

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