Rendering in Revit; raytrace - no radiosity. Subsequently a wireframe *.jpg is exported of the same view.
The two images are overlayed with the hidden line on top. Then the wireframe image is modified to +/-25% transparency.
The final result has a nice sense of lineweight without seeming overly resolved. And the highly transparent underlay also provides a good degree of the internal space/form without being too literal.
All the best -
Phil