Some wonder where the facets in curved surfaces come from in their prints. One source is in the conversion from the modeling software into the STL mesh. These are all the same model exported to stl with 4 different settings. The numbr in the file name is the triangle count from 3,348 up to 540,398. With complex models the triangle count can get out of hand fast and can overwhelm slicers or make print files huge so you have to find the balance.