Rolling Knot

thingiverse

I discovered mathgrrl's rolling knot at http://makerhome.blogspot.co.uk/2013/12/day-110-rocking-knot.html and decided to design it using Openscad. The challenge was to create a smooth, fully rendered tube within an acceptable time frame. Initially, I attempted a tube made of oriented cylinders along the path, but this method proved slow and rough. Following nophead's suggestion, I switched to segments formed by hull()ing successive pairs of disks or spheres. Surprisingly, the script for spheres was not only simpler but also faster. Nophead then recommended using a cone instead of a disk, and adding explicit render()s further improved performance. The best script, "rolling-knot-hull-cone," renders the 2 degree version (180 segments) in 12 minutes on my Acer Aspire. I'm grateful to mathgrrl and the helpful OpenScad community, particularly nophead.