I'm editing the "dea_bldg_reactor_room_corridor" in soft-image and the model works in the game BUT the floor is black and I want it to be a bit transparent just like the "dea_bldg_reactor_room_corridor". I'm guessing I need to do something with floor in soft-image to make it the same level of transparency as the "dea_bldg_reactor_room_corridor" floor. Can someone please guide me through this, I don't really work with soft-image that much

Thanks in advanced

It will show up as opaque in Softimage, but it will still be transparent when it's in-game as long as you don't remove the transparency material flag. In other words, don't worry about it not being transparent in Softimage. It'll be fine.