Parametric sine, parabola, ellipse, examples of 2dgraphing

thingiverse

This is a remix of 2dgraphing.scad from https://www.thingiverse.com/thing:11243 to make the sine wave, parabola, and ellipsoid (and ellipse) examples available in the customizer. Note that the parameterization is awkward, since I repurposed some of the variables to work for all these examples. In the customizer "Amplitude" is the Y-axis height, and "length" is the X-axis length. For the ellipsoid you may need to set a higher epsilon to keep the ends from intersecting with each other due to [constraints in '`rotate_extrude()`'](https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/2D_to_3D_Extrusion#rotate_extrude) The frequency of the sine wave, `omega`, is given in radians/millimeter, so `omega= 2*pi/200mm=0.0314159` would give a 200mm, and `omega=3* 2*pi/200mm` would give three cycles in 200mm. I used this library to make the traces in my sine wave bed levelling test: https://www.thingiverse.com/thing:5516205 The nice thing about using a sine wave for a bed leveling test is that the path is always changing direction, so if adhesion is poor, the sideways motion will break free and show you where adhesion is bad.