Chaps,
@dkightley - I know this is "just how S3D works...", I've just found that out, but I think it is wrong or at least counterintuitive and that's why I'm reporting it as a bug.
@horst.w - In the Support Generation dialog open there is an option to "Export Supports", that's how I am exporting the supports, I'm guessing it is a feature you have not used, and in fairness it's a feature I have not used until recently either. Your suggestion of switching profiles after placing the supports kind of half solves the problem, but I then need to change a bunch of process defaults in the profile to get the best out of my printer, which is a manual and error prone process at best.
I do have a multiple profiles, one per printer, with all the tweaks needed to get the best out of that printer/filament.
But, if I import the same model into a second profile, then the previously exported supports (saved in the same directory as the model's STL file) are also
auto imported, but are placed in the wrong location because the build plates differ in size between the two printers. My only option at this point is to manually delete all the supports, add in the default generated ones, and start adding manual supports again, another manual and error prone process...
It just makes more sense to have supports touching a model (which is of course the only place you can manually add the supports anyway) to be associated with a model specific origin, not the printer's origin. And this applies doubly so if the supports are going to be auto-loaded when I import my model.
I can see how it would get messy when you have multiple copies of the same model on your build plate, in that case maybe the support information should only be included with the factory file, and the option to export the supports should be disabled.
Disclaimer: I'm a software architect and UI designer, but I wasn't involved in the design of S3D.