Modeling a "plaza" in blender, using a 2D base from AutoCAD.

1) Export from AutoCAD's DWG  to DXF so I can import into Blender.

2) First error (i just "love it"), let's try again 

exporting  to a older DWF version..

3) Yeah, it worked. but lacks details which I need to see what I really

need to draw.

4) DXF result was not cool, so I exported it to PDF with real scale. 

From PDF, I then exported to JPG image (high DPI) and

scaled according to the drawing scale.

5) Right side of the "plaza". Nothing more than drawing over the reference image, using bezier, plane, etc then extrude. Attribute basic 

colors to know which material to use later and separate functions.

6) There are a lot of ways to draw over an overlay (reference). 

A) You can draw a plane or any other mesh, 

then use a boolean modifier like in (1): 

(2) is a more advanced mesh, created with the curve tool:

b) Or, like this case, I created a plane then I'm splitting it

 with the knife tool, then later I will create separated regions...

..because in this "n-gon" it's hard to separate regions. 

Some extrude here and there...

This is the first part. The next will be texturing and inserting models (Tress, benches, bicycles, etc.)