a term used by hardcore anime/manga enthusiasts who think that anime/eroge characters are more attractive/like them better than real girls, the term is used to describe ones disgust with real women. This term is often used by regular visitors of the anime/manga related boards on 4chan. The term "3d pig" includes every real woman however, in many cases Japanese women that are attractive are excluded from the term.
Anonymous1: "oh lawd (insert famous hot female's name here) is so hot, post pics of her, i'd hit it"
Anonymous2: GTFO 3D PIG DISGUSTING