Thanks @DKirch, grateful for you looking into it. A year is plausible; I hadn’t been using the auto-orient button for a while and I also might have been on an older Preform for some of that time.
Here’s an example where I think it missed out:
The one on the left was suggested by auto-orient. It didn’t want to suggest any upside-down orientations even though anecdotally we’ve found that tends to be a good option for these kind of models (which admittedly have some stupidly thin features and are rather tricky).
I’ve also noticed Auto-Orient get “stuck” on a particular orientation sometimes. e.g:
It kept just suggesting the one on the left over and over, which has lots of minima (again compared to that manual one on the right which requires fewer touchpoints).
Or this one, where it first suggested an orientation having a massive overhang:
After about four tries it got closer to the “design” intent:
But then it got stuck there and kept suggesting orientations that were only a degree or two different. Not sure how to “reset” the search short of re-importing the STL.
It would also be awesome if there were a “tweak orientation” button that constrained the search space to solutions near the existing one. The idea would be you get it in approximately the orientation you want by hand, then rely on the software to perfect it. Just food for thought.
I swore I had some better examples (like where it was leaving unsupported islands when there were rotation tweaks that could eliminate them) but I haven’t been able to recreate them at the moment.
Maybe if I get some time I’ll fire up a Preform from more than a year ago and compare results. If so, I’ll let you know if I turn up anything interesting.