Attached Link: Free SciFi Stuff Here!

Yep, like randym77 says, size is the main issue. Poser in particular just doesn't handle huge very well;)

If you're not hung up on windows, you can find lots of interior pieces and move them into place to link up so that you could have an animated figure walking straight through the ship without any cuts, if that's your goal. Design may be an issue, but there are Trekish starship bridge (complete with turbolift), engine room, and transporter room sets in my free stuff that are all designed and textured to go together. And an observation lounge that could fit in fairly well, too, that does have windows. And there are a couple of corridor sets that you might be able use to link things up. Aside from the observation lounge, these could be inside pretty much any starship exterior and no one would know. It's not like they're that precise about these things even in the movies...;)