I understand this is a very basic question, but I cannot find the solution. Google & other Stack Exchange gave me no solution either.
I am following Blender Game Asset Creation guide from Blender Cloud, at some point Aidy selects his whole model and does Shade Smooth. Then he selects some edges and marks them sharp.
In Aidy his tutorial you can clearly see the difference between marking sharp and not. As seen here (this is taken from his tutorial)
When I do this in my Blender File, I see no difference. I've tried removing any doubles, but I can not think of anything else. What could be causing this?