First sorry for mistakes in my english (I am not native english speaker).

You need to know what do you need? If you need landscape if I were coder in your team I would do my own landscape generator. If you need 3D map like is in Quake or Unreal you also need your own map editor. If you need 3D models you can use 3D Studio or Meya but you propably be using it only to 3D model (vertex, faces and textures) because the light etc is made by game engine so most of complicated tools from Meya or 3D Studio won't be use. You can use also some cheeper program like MilkShape. You also need to talk with programmer about fle format that he know how to load. Usualy 3ds and ase are easy to load. In my game I converted 3ds to my own format and my game is using my own format, because even 3ds file have much information that I don't need.

best wishes
mgk
If you are graphic, musician, sound maker and you want to help making a game please contact with me.
My project http://mgkiler2.republika.pl/game.zip
my e-mail: mgkiler2@poczta.onet.pl