One of the most irritating things about sketchup its its tendency to explode a beautiful arc from autocad into a billion straight segments, as well as turn larger arc radius drawn in SU into jagged lines as well. Whenever I draw a curved pathway, wall, etc., I have to go back and manually draw little arcs just so you don’t see these jagged edges (which are more pronounced when you bring them into lumion, vray, etc.). One time, someone showed me a way that you can reduce or increase the amount of lines SU uses to create an impression of “smoothness”. Is that a feature withing SU or an extension?
You might have a look at the tools in Fredo6’s Curvizard. Also, when you are drawing curves in SketchUp you can choose the number of segments used from the beginning.
After importing an autocad drawing you can modify the number of segments. Here is a circle that Sketchup imported as a DXF. Sketchup set the number of segments to 96.
This is true if SketchUp recognizes the geometry as a circle or arc.