I like to experiment with designing 3D-models on my computer.
I use Google's SketchUp.
Development and changing a 3D-model is fast and easy - you can cout out the model and put it on your layout.
to unfold the Sketchup-models I use TAMA-Soft's Pepakura-Designer.
I'm able to fit glue flaps and can put pictures of the completed model and texts explaining the process on the page which I store as a PDF. This can be printed and built as often as you need.
After construction the models look a little bleak. But it is astonishing how many details can be seen on a decently textured model. And moreover you can superdetail them by adding rain drainage or balcony meshes or even flower boxes to the windows.