I am building a car engine and I want to set it to smooth shading. But for some reason it does not work. Has anyone an idea how to fix that?
Here you can download the .blend file.
You have an edge split modifier which is causing the faces to look like they are not smooth shaded, but they are.
The edge split modifier is splitting the surface into individual faces so it is no longer a single surface that can be smoothed.
Increase the edge split angle on the modifier to reduce this effect.