As far as I can remember, only one robot in Twisted Metal has a nose, and she uses this to sniff petrol. Although all the robots on the planet Penrose have the capacity to install a nose, very few of them choose to do so. The robots of Shull, in particular, live in a place with very few organic compounds, and so have little reason to smell things. They prefer to use the metal to make something else.
It probably wouldn’t surprise anyone who has ever been on a writing course to discover this made writing the book (and the sequel) something of a challenge. Would be writers are always advised to make use of all five senses when describing things, and this is good counsel. The sense of smell is particularly evocative (the smell of the sea and sun tan lotion always makes me think of holidays, for example) and to remove this sense from the book was a great wrench.
But I had to do it. The novel is written from the point of view of robots, and the robots in the book have no need to smell things.
Did it make a difference to the reader of the book? Did anyone even notice? I’d be interested to hear what people think…