2015-12-14 (M) ESPeri.Impass

Yesterday's sketched plans were modeled in OpenSCAD. A large spinner was modeled with a hollow cavity and a conical top. The conical top was to allow a pin, or usually a mechanical pencil, to rest in the apex and ensure it would be centered. The model was created right-side-up but printed upside down so the inside of the cone would receive the best finish.

Spinning model 1

Printed model top

Printed model underside

Slope on the cone proved to be too gradual so the model was modified to have a steeper slope. To conserve plastic only thin shells were printed which became problematic as the plastic delaminated. Several prints were unusable because the fragile shells became tangles of plastic extrusion rather than recognizable shapes.

Three failed prints

Printing the spinners upside-down used supporting material which had to be peeled away and left unwanted strands. These strands were unattractive but they could potentially unbalance the spinner. The low center of gravity built into the spinner would counter a lot of imbalance by virtue of its design.


Several iterations and prints were made to create a model which had a steep cone and could be printed without support material. Unfortunately this version used significantly more plastic although the gain outweighed the cost.

Final model of the day

To do:
  • Model parametric spinner
  • Make free spinning base
  • Optional:
    • Add compass rose to spinner
    • Add holes to reduce plastic
  • Add “keyed” features to only allow slop when facing north
  • Make handheld haptic compass
  • Make compass work from pocket or necklace
  • Miniaturize

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2



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2015-12-11 (F)

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