Ignoring the Alien v. Predator films (can I do that please?) Alien was our first encounter with the titular species. Ridley once joked about doing a movie about the Space Jockey, though, but even they seemed unfamiliar to our human characters.
Actually, there are various parts of Alien which can be interpreted as the Company having some knowledge of the Alien. Ash seemed more familiar with it than he should have been anyway.
But anyway, 3-D? Groan, I'm already getting tired of it just because of all the news and rumours of upcoming films supposedly going to be in 3-D.
And what would 3-D bring to an Alien film? Facehuggers jumping at the audience?