You could probably whip up a diagram like this in SketchUp.  Its free and pretty simple to use.  Push-Pull is your friend.  Plenty of tutorials online and a bunch of handy plugins.

Thats actually done in Vray (probably 3d Max Vray) but you can do it in rhino.

In 3dmax Vray you basically run an ambient occlusion along with contour .

If you do it in Vray Rhino just run rendering with no materials and then do  a make 2d of the same view and overlay it. Both techniques take about 15 mins max

Look at BIG architecture they do this the best

I have been drawing diagrams all semester my hands have calasis and my teacher's voices still rings in my ear DRAW........KEEP.......DRAWING!!!....LOL and i work 40hrs a week I have'nt used software to draw a diagram yet though.

White box rendered in max with ambient occlusion only, then overlay the 2d linework.

That's not a diagram. 

^anonitect is right.  it's an aerial view of a city block.  the generic rendering engine in rhino can do that.  no need for v-ray.  

MyDream what do you mean you draw diagrams by hand?  that seems absurd.  i hope they aren't 1970's era bubbly colorful arrows twisting through a floor plan...

Im pretty sure this is pulled directly from a recent tutorial posted on ThinkParametric (no really - its there). It used Rhino and Vray from what I remember.

But like the others said, this isnt a digram, its simply an axonometric aerial view.

the easiest way is Sketchup, take a 2D screenshot and adjust it using illustrator. 

^ no. whoever said ambient occlusion rendering in 3dsmax / rhino with toon materials is right. that is the quickest process.

Easier still- Install Neon for Rhino and render and just take the screen shot.

@cinnamonrollarchitect

I think that was made in Revit, or Vasari.

But is that a diagram? 

just do it in Rhino RAY render with no material and make 2d of the line and go into adobe and assemble and put the render @ 10-30% opacity and boom takes like 2 min