Create and modify 3D models > Create 2D geometry > Change 2D geometry > Convert 2D geometry
  
Convert 2D geometry
You can convert construction geometry into 2D geometry.
1. Click Modeling and then, in the Modify 2D group, click More.
2. Click Convert Geo in the Tools section.
3. Click the geometry edges.
4. Click to complete the operation.
This command does not work on infinite straight construction geometry.