AGrau95

Thank you so much, this was the issue. I may have left it checked when I was toying around. 😄 Have a nice day!

It was already unchecked

Thank you for your time, I tried your suggestion, but the problem persists. I also tried to remesh it with blender. Same results.

It's from thingiverse. https://www.thingiverse.com/thing:3180500

Good morning all. I'm trying to print this simple piece but when I slice it the internal hole gets filled by Cura as if it didn't exist. The model is watertight. I tried also to disable Union overlaping volumes without results. Can somebody point me in the right direction? TRD_spiral_stairs.stl