Connecting edges in sketchup

Hi, I often need to download dwg files from manufacturers website (mainly typical details such as roof profiles or fixings)
The issue is that after importing into sketchup, I receive the correct drawing but it is broken into thousands of little line segments which are making it hard to trace (especially curved lines) and very time-consuming.
Can anyone recommend a way to join all these edges into a single face that I then can push/pull into a 3d model?

You need to weld the edges (I use Weld from the smustard extensions) and then you can often simplify the edges with Simplify Contours from the SketchUp Team.

Both easy to install through the Window-Extension Warehouse.