I had the same experience the one time I tried it. It seemed like it might be trying to do a “ramming” sequence like used on the XL, but it just jammed my extruder. I haven’t tried it again. If you have the time and motivation, it’d be great to submit a bug report to Prusa.
Interesting, it took me a while looking at your images to figure out why the original design didn’t work. The problem was that there was no solution that could avoid at least one extremely long bridge, and that bridge also forced the adjacent bridges to be “wrong” (though maybe if it printed the super long bridges first, it could’ve made the rest short).
I don’t have much to add besides being surprised the problem was more interesting than it first seemed…and I don’t accept that you were being an idiot because it want immediately obvious to me either. Or I am one too :)
especially if it were printed vertically, i.e. you would be pulling the final product into your extruder in such a way that it would be pulling against the layer lines.
I agree that vertically-printed filament would have poor tensile strength, but isn’t most of the load from the extruder going to be compression, shoving it from the extruded gear to the melt zone and nozzle? Other than during retractions, doesn’t the tensile stress just comes from pulling the filament off the spool?
What about printing it in two halves the each have a flat bottom? Since the optical quality doesn’t matter, the line down the middle of the lens won’t matter.
In practice, I haven’t found the print volume of my MK4 to be too limiting. Occasionally more X/Y would be nice, but plenty of parts that are too big for my printer would be too big for any printer and still need to be cut. The other issue is that even fast 3d printers are slow and I don’t really print things that take entire days. Even printing dactyl keyboard halves takes hours thanks to the need for supports, so I can’t imagine someone frequently doing really huge prints (particularly in height).