While the current “Freestyle for Blender” development allows only for pixel based stroke renderings, many of us would wish to export the current view as a vector drawing. The script embedded in the linked blend-file allows you to project the selected meshes on a plane according to your camera parameters. The plane can then be exported to a DXF. No orthogonal projection yet (see yorik’s guestblog for an alternative on that or extend the script). No hidden lines removal.

File: 2D-Projection.blend.zip