Extended Archimedean Spiral Module

thingiverse

While crafting a pancake-primary mounting fixture for a Musical Tesla Coil, I required generating an Archimedean Spiral to simulate the location of the primary wire in the fixture. I discovered the [Archimedean Spiral Module](https://www.thingiverse.com/thing:1267784) here on Thingiverse and it was a great starting point. However, it only starts at an initial radius of 0 and only lets you specify the final radius, which led to incorrect spacing and positioning for my application. Instead, I needed to be able to give a starting radius and a spacing for the spirals, and add an arbitrary start angle to rotate it to the correct angle for the fixture. So I modified the module and created this Extended Archimedean Spiral Module. This module contains the `archimedean_spiral_ex()` function with the following parameters: `spirals` = how many spirals (positive=CCW, negative=CW), can include partial spirals `thickness` = how thick you want the arms to be `startradius` = beginning radius position `spacing` = spacing between radial points `startangle` = angle to begin first sweep `center` = 'true' centers the spiral arm thickness (default=true) It incorporates the following changes from the original design: - Arbitrary starting radius - Specifying of the spiral spacing instead of final radius - Arbitrary start angle - Rounding of the end-points to the nearest `$fa` angle to allow for fractional rotations without drawing it weird - Centering option to center the specified thickness of the spiral arms - Ability to draw the spiral clockwise or counterclockwise by using a signed number for the number of spirals UPDATE (9-18-2018) : Changed the polygon start and end position by `$fa` so polygon always starts on the correct `$fa` angle boundary.