Having been tuning designs a lot recently to minimize support implications for 3d printing I am aware of how massive a difference this tweaking can make to reduction in the support material / time / reliability of print / surface finish impact.
A little effort makes a night and day difference to all these factors.
What would make this so much easier, and something I don't think I have seen elsewhere is the combination of these two workflows.
1. Make it possible to export STL at the body level using any construction plane as the reference plane for down. Presently to force the orientation of parts for STL export so that my flat model face I wish to have down is aligned to a origin axis, I have to export the part out of the main design, where it may be in a complex orientation to a separate design. Host it in a new component within that design, draw a circle on the origin plane via a sketch, then using a joint defined on the "down" face of the body, joint the body to the sketch. Then I have to export from the root of the design, or it doesn't observe the intent of the orientation. If you could simply define an arbitrary plane as the "down" during the STL export of the body at the node in the browser, it would make export in place with easy orientation so easy. This is important to ensure you get absolute alignment of the down face in the slicer package you may use, Makerware for example, if you have to manually tweak you can be sure your face will not be perfectly aligned, and this means poor finish. It also empowers point 2 below.
2. Add an analysis feature that, colorizes the body faces according to angle from the selected "down" plane. Using this and a parameter that represents your printers capability to build overhangs without support, lets say 45 degrees for the purposes of this description, you can color faces that are up in relation to the down plane as "passive", faces that are down but shallow enough to not require support as "healthy", and those approaching the angle where support is required to those where it is definitely required to varying shades of "needs attention" with a good contrast where that boundary angle is crossed.
You can then work directly in fusion to prep your model, where angles can be adjusted or down face chosen differently without compromising your design.
This would be so much faster / convenient than the current workflow of exporting STL and examining in various external packages that visualize support output.
If this already exists in fusion then please point me at it.
I assume it should be similar to draft angle analysis for molded parts.
Yours in hope.