Why region is set to be slightly larger than geometry?

MFiX
#1

Hi, Developers

I notice that when region is set to fit the geometry, such as cylinder, automatically, the size of region is slightly larger then the geometry. I would like to know the consideration behind this setting you made. Is it benefit for the mesh quality? or other?

Thank you!

#2

The box extent are a bit larger so the box coordinates don’t have too many decimals and the stl is not clipped.