[GIS] Creating building shadows in QGIS

Question

Can anyone think of a simple way to create a polygon to represent building shadows?

I have a shapefile with height information for the buildings and I want to create a simple plan looking like the image below:

I don't want it to be accurate based on the terrain etc or really specific of the sun, but just a way to demonstrate the height of the building with a shadow that is connected to the building.

Answer 1

Use Translate, in the toolbox:

here I set dx and dy both to .71*Height to simulate a 45° sun incidence, but you can use whatever combination you prefer.

This creates a new layer, which you have to move under your original one, and set to a dark shade. Optionally, for a smoother rendering, set a slight blur with the Draw effect: