When will ArtiosCAD convert an arc to a line during a DXF/DWG import?
ArtiosCAD will convert an arc to a line during a DXF/DWG import when the radius of the arc is significantly larger than its length. Specifically, when PD below is < .005mm. (PD is the midpoint of the arc projected onto a line joining the endpoints of the arc).
This is done to minimize rounding errors when the radius is very large.