The most common reason an STL file may be not quite right is a mechanical connection where some piece isn’t quite as the designer expected, so the 3D model that interfaces with it no longer fits.

STL files: STL files created by most major CAD systems execute without any glitches. A few off-brand CAD programs do indeed create STL files that have problems, however.

An imported STEP file is converted to a triangle mesh on import (making it much like a typical .stl or .3mf file) which means that slicing all happens as one would normally expect.

Microsoft has picked up Netfabb's 3D file cloud repair service, and renamed it Microsoft Model Repair. Features faster repair times thanks to new servers.