JoeJ wrote:It seems like this might help support the roof, but it does nothing to make the sides of your part stronger. Personally, I would rather have my entire part be strong in all directions than some type of directional support. Also, infill definitely won't support large overhangs like that very well since the sparse spacing will create a lot of drooping. Perimeters act very differently than infill with regards to overhangs like that.
You just add more perimeters for your walls to make them stronger, this would be an extra option, not replacing the normal full infill. Not every print needs high strength, for prototypes or models. I'm building a printer with a 24"x24"x34" print area. A feature like this would save so much time on large objects.
It would easily be able to support large flat tops with this, it would still use the same infill options like density, etc. I'm pretty sure all printers out there can print at least 45 degree angles, for the infill to meet the top surface.
Also think about for more complex models, say a model of a space ship, maybe only a few parts would need infill on the top to create details, instead of having 2 feet of infill just to support a couple small overhangs... just make an inch or 2 of 45 degree infill from the wall. Using 4 perimeters would be plenty strong and thats way more time saving, then full infill.