Strutted Z-Beam - tetrahedrons

thingiverse

Modified version of gringer's OpenSCAD implementation of RepRap Ltd's "3D printed beam that is as stiff as steel" Modifications are to restore the alternating diagonal directions, to add the internal diagonal beams as per RepRap Ltd's original design, and further to make it all tetrahedrons. RepRap Ltd describe the tetrahedron-based internal structure as key element of the structure's strength - since in their original the internal diagonals alternate in direction on each layer but the side diagonals don't, it's not all tetrahedrons. By default this OpenSCAD code fixes that - switch off "fixup"* to get the original configuration. The side diagonals are still slightly different from RepRap Ltd's original, but I'm not sure that was a deliberate choice in the first place. * I note the fixup parameter isn't supported by the Thingiverse customizer; use OpenSCAD instead