set designer,

You should note that SketchUp doesn't actually do curves. All circles, arcs, bezier curves, etc. are composed of straight-line entities.

After import, you can select a curve and change the number of line segments, if you need a smoother 'curve.' (At least, that is usually reported as effective.) After selection, look in the 'Entity Info' dialog box, and therein change the number of segments.

Taff