Non Circular Gears

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Non-Circular Gears - A Functional Programming Adventure in openSCAD I'm thrilled to share my first attempt at heavy-duty functional programming in openSCAD. It's not lightning-fast, but it gets the job done. A C# program will calculate results within 10-100ms with a whopping 16,000 iterations. However, I've limited the number of iterations by recursion max, and even then, it takes around 40 seconds to calculate, often longer up to 8 minutes seen. The number of iterations could be reduced, but the best results come from high numbers, so I've left it at a comfortable 5,000. Be warned: with numbers higher than 5,000, you'll start encountering recursion errors. Important Note: * Only enable one drawPolarGearSet at a time, as each can take several minutes to calculate and lock openScad until done. * If you experience recursion errors, try the following: + Edit > Preferences + Advanced tab + Set "Turn off rendering" to 4,000,000 It works on my setup! More information about Non-Circular Gears can be found in my article on CodeProject - search for "Drawing Gears - Circular and Non-Circular". This all-inclusive openSCAD version is more user-friendly than the C# version, which requires additional support programs like Sketchup with STL export add-on to generate STL files and some knowledge of Ruby. If you don't want to mess around with parameters in openSCAD, STL files are ready to be printed! Naming Convention for STL Files: * major axis * minor axis * power * revolutions * centerInFocalPoint * maximumLengthBetweenPoints * numberOfTeeth Scaling Applied: * Scale 0.85 has been applied to: + 25_15_4_1_true.stl + 25_15_4_2_true.stl + 25_15_4_3_true.stl + 25_15_4_4_true.stl (to ensure the largest gear fits my printbed) * Scale 2 has been applied to: + 15_15_4_1_false_dot125.stl + 15_15_5_1_false_dot125.stl + 15_15_6_1_false_dot25.stl + 15_15_7_1_false_dot35_48.stl + 15_15_8_1_false_dot35_64.stl + 15_15_9_1_false_dot40_72.stl (to ensure fine teeth on the last gear can be printed) All other STL files are unscaled. To-Do: * Other parametric gear designers have added helix, herringbone to normal gears and planetary gear sets. * Plan to print more gear sets and study their behavior under load forces. * Scaling was done in ReplicatorG as I prepared the STL files for printing. You can do it in openSCAD before saving the STL file with a small code change. For the mathematically inclined, this project offers plenty of opportunities for learning: * Best search algorithm to find optimal center distance? * Why does the method used work better than standard binary search? * How to speed up calculations in a language with many limits? * Skipping calculations and tweaking tolerances * Overcoming jump values in power functions used to generate superellipse data * Getting enough data points for good approximation of perimeter length/tooth placement Have fun!