Extrude-Scale by Function: Propeller

thingiverse

WilliamAAdams suggested, quite rightly, that the various extrusion parameters I've been doodling with could be controlled by functions... and I pointed out that the thing being extruded could be any 2D shape at all. As a semi-practical application of these two ideas, this is a four-blade propeller made by extruding the union of a square and four rectangles while scaling that union according to the cosine of the extrusion height (with some twist thrown in, of course). The layers are 1/4 mm thick. Instructions It took 2 hours on this recentish latop to render the STL, but you can probably live with thicker layers, which would render faster. Skeinforge sliced it with no problems. Play with the OpenSCAD script, or print the STLs directly. GitHub repository: github.com/syvwlch/Thingiverse-Projects/tree/master/ScaleExtrudeHorns