I've never really given much thought as to how these guys do the background art in manga. I've always thought that they were very good at drawing straight lines (seeing how they come from generations of sword-wielding samurai culture) & I've heard that they've even used photocopy/filtered versions of real photographs. But silly me, I've never realised that they've been using 3D modelling softwares to model the background sets & then render them as 2D lines.
Ooohh, Ahhh. So desu ne! That made me felt really, really stuupid.