Extrude-Scale by Function: Propeller

thingiverse

WilliamAAdams proposed that extrusion parameters could be managed using functions and that any 2D shape can be the item being extruded. A practical application of these ideas is a four-blade propeller, created by extruding a square and four rectangles while scaling based on cosine of the height, with a twist included. The layers are 1/4 mm thick and took about two hours to render on a recent laptop, but you may opt for thicker layers for faster rendering. OpenSCAD script can be played around with or STLs can be printed directly from GitHub repository available at github.com/syvwlch/Thingiverse-Projects/tree/master/ScaleExtrudeHorns.