Unity supports triangle meshes and not Polylines

I am working on a project in which I need to import AutoCAD *.dwg files in Unity. To import them in Unity I convert the DEG firl to DXF file .When I import these files from Import assets option and then drag-drop that asset in scene view, the asset does not appear.

My DWG file is made up of Polylines and not triangle meshes. So does not Unity supports Polyline meshes? If not, how I can convert my DWF/DXF files from Polylines to triangles?

Thanks,
Hitesh

it sounds like the polylines are contours, and you expect unity to triangulate them for you.
A polyline is not a mesh so there is no such thing as a polyline mesh.
You will need to add the plines as contours or breaklines into some software like 3ds max or sketchup that can do the triangulation, then export as fbx I think.
Not sure if Civil3d surfaces play nicely with fbx, but you could likely export c3d via imx, then open in 3dsmax and convert to fbx.
I myself am looking into the ways of getting triangles from other programs into unity.