Parts. I acquired the following parts: • One N20 6VDC 50RPM gear motor. • One 3VDC power supply. I 3D printed the following parts: • One "Arm, Left.stl", .1mm layer height, 20% infill. • One "Arm, Right.stl", .1mm layer height, 20% infill. • Two "Axle, Arm.stl", .15mm layer height, 20% infill. • One "Base.stl", .15mm layer height, 20% infill. • One "Body.stl", .15mm layer height, 20% infill. • Two "Bolt, Mount, Motor.stl", .15mm layer height, 20% infill. • One "Cam.stl", .1mm layer height, 20% infill. • One "Guide, Yoke.stl", .15mm layer height, 20% infill. • One "Mount, Tree.stl", .15mm layer height, 20% infill. • One "Mount, WIng, Left.stl", .1mm layer height, 20% infill. • One "Mount, WIng, Right.stl", .1mm layer height, 20% infill. • One "Retainer, Mount, Wing, Left.stl", .1mm layer height, 20% infill. • One "Retainer, Mount, Wing, Right.stl", .1mm layer height, 20% infill. • One "Wing, Left.stl", .15mm layer height, 20% infill. • One "Wing, Right.stl", .15mm layer height, 20% infill. • One "Yoke.stl", .1mm layer height, 20% infill. This mechanism is a high precision print and assembly using at times very small precision 3D printed parts in confined spaces with highly precise alignment. I printed parts using the Ultimaker Cura 4.7.0 "Engineering Profile" on my Ultimaker S5s, which provides a highly accurate tolerance requiring minimal if any trimming, filing, drilling or sanding. However, prior to assembly, I still test fitted and trimmed, filed, drilled, sanded, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on your slicer, printer, printer settings and the colors you chose, more or less trimming, filing, drilling and/or sanding may be required to successfully recreate this model. I carefully filed all edges that contacted the build plate to make absolutely certain that all build plate "ooze" is removed and that all edges are smooth using small jewelers files and plenty of patience to perform this step. This mechanism also uses threaded assembly, so I used a tap and die set (6mm by 1) if required for thread cleaning. Base Assembly. To assemble the base, I performed the following steps: • Soldered 60mm lengths of red and black wire to the motor. • Pressed the motor into the motor mount on "Base.stl". • Pressed "Cam.stl" onto the motor shaft. • Placed "Guide, Yoke.stl" onto the base assembly, then secured in place with "Bolt, Mount, Motor.stl". • Positioned "Yoke.stl" into the base assembly. • Secured "Arm, Right.stl" onto the base assembly using one "Axle, Arm.stl". • Secured "Arm, Left.stl" onto the base assembly using the remaining "Axle, Arm.stl". Angel Assembly. To assemble the angel, I performed the following steps: • Positioned "Retainer, Mount, Wing, Right.stl" in right slot on the back of "Body.stl", then slid it fully upwards. • Positioned "Retainer, Mount, Wing, Left.stl" in left slot on the back of the body assembly, then slid it fully upwards. • Positioned the base assembly near the bottom of body assembly, inserted the motor wires out the hole in the rear of the body assembly, then pressed the base assembly into the body assembly and secured in place with small dots of cyanoacrylate glue. • Pressed "Mount, Wing, Right.stl" into the slot in "Wing, Right.stl". • Pressed "Mount, Wing, Left.stl" into the slot in "Wing, Left.stl". • Positioned the right wing assembly in the right wing slot making sure the pin on the wing mount slid into the slot in the right arm, slid the wing assembly down onto the right pin on the body assembly, then slid the right wing retainer down over the pin on the right wing mount. • Positioned the left wing assembly in the left wing slot making sure the pin on the wing mount slid into the slot in the left arm, slid the wing assembly down onto the left pin on the body assembly, then slid the left wing retainer down over the pin on the left wing mount. • Applied power to the mechanism and performed final adjustments to the retainers. Once I was satisfied with the wing operation, I secured the retainers in position using small dots of cyanoacrylate glue. • Soldered the power supply wires to the motor wires and insulated with heat shrink tubing. • Glued "Mount, Tree.stl" to the bottom of the assembly. And that is how I 3D printed and assembled "A 3D Printed Animated Angel Christmas Tree Topper". I hope you enjoyed it!