doodling this morning before my first cup of coffee started to work. Varying pitch and diameter with a taper in the last turn or so. Totally in SketchUp. I was told this can’t be done in SketchUp. Maybe I’m doing it wrong.
SketchUp may only be able to model things with bounded planes, but if they are fine enough, they effectively make a smooth surface. Even when 3D printed, if the facet size is at or below the resolution of the particular printer and media, the result can be smooth as needed.
When I first used SketchUp, I wanted to make a bolt with a screw thread. This led me down the rosy Ruby path of creating a plugin to make threads. Which led to adding various transformations and options until it was no longer a usable tool. However, once you understand what it wants to do, you can make a whole lot of helix doodles
I think the thing that makes SketchUp so flexible is that there are so many ways to skin a catfish. If the result is what you want, then you must have done it the right way