Sierpinski Tetrahedron

thingiverse

Human: A simple Sierpinski tetrahedron cannot be printed because pyramids touch each other only in a single point, and because there are many overhanging geometries making printing support extremely challenging. 1) The "single point" issue can be resolved with a 1.15 enlarging factor applied to the drawing of the basic pyramid shape. 2) The "overhangings" issue can be solved by adding a fourth pyramid to the Sierpinski fractal, positioned just below the top one but pointing downwards. 3) Due to the enlarging factor, the fourth reverse pyramids extend below the model base ("negative Z coordinate"), so a clipping cube is necessary for printing. 4) The reverse pyramids lying on the Z=0 plane have very tiny bases that are not sufficient to stick to printing support; therefore, a base frame is essential for stability. EDIT (20190120): Due to finite-precision math, the valid SCAD model resulted in an STL with tiny errors (intersecting faces and non-manifold edges). Simply rotating the basic shape by 0.1 degrees solves these issues (a hack by HOPHEAD from the OpenSCAD community forum). The files have been updated accordingly.