“Something that can automatically generate a turbine or propeller? This OpenSCAD script does just that! Generate very quickly a parametrised turbine or propeller. Arguably the best one on thingiverse? t is quite complete, here I list its features: Clockwise/ Counter Clockwise rotation; Leading edge of blade can be curve (an Arc) or straight. A module is created to generate arcs (OpenSCAD can’t draw Arc primitives); Trailing edge blade can curve inwards (I call it ‘convex’) or outward (‘concave’) and this can be defined with an exponentiation function (you decide the base or power); See: https://en.wikipedia.org/wiki/Exponentiation ; There’s an offset parameter, allowing you to prescribe, when curvature begins (applied)…; Of course, number of blades, length, height, thickness, stem radius, shaft radius, etc…”