Extended Archimedean Spiral Module by dewhisna

Last crawled date: 3 years, 1 month ago

While designing a pancake-primary mounting fixture for a Musical Tesla Coil, I needed to generate an Archimedean Spiral to simulate the location of the primary wire in the fixture. I found the Archimedean Spiral Module 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 wrong 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 spiralsthickness = how thick you want the arms to bestartradius = beginning radius positionspacing = spacing between radial pointsstartangle = angle to begin first sweepcenter = '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.