Customisable, parametric 3,4, 5 (or more) sided funnel

thingiverse

VERY IMPORTANT. The STL files generated by this code produce a solid object which isn't very useful as a funnel. To get a hollow funnel, you should adjust your slicer settings to exclude the TOP and BOTTOM LAYERS, set INFILL to NONE, and choose 3 or more PERIMETERS (SHELLS). A circular funnel may not be practical if you need to fit it into a tight space or want it to blend in unobtrusively with the corner of a planter, for example. This code will create a triangular, square, pentagonal, or whatever-sided funnel you require. There are only two variables you need to input: the size (width) and how many sides (3 for triangular, 4 for square, 5 for pentagonal, etc.). The higher this number is, the more "round" the funnel will be. All other dimensions will be derived from these two inputs; however, if you want, you can experiment with the Open Scad variables to adjust the other proportions. The height of the funnel will be about 95% of the width, so don't make the width any larger than your maximum print height if that's 150mm. Note that this code utilizes the $fn function of Open Scad to limit the number of sides of a circular object. Therefore, the width you enter is actually the diameter of a circle which will touch the corners of your funnel. If you want a square funnel with flats measuring 100mm across, for example, you would need to multiply this by about 1.4 to get 140mm across the corners. I have included a few STL files as well as the Open Scad file to give some idea of what is possible.