This is the Kushan Mothership from Homeworld. It comes in two versions: One with the large cargo bay door filled and closed, and another open with the door separate.
The version I printed (files 01 and 02) is with the door closed, model rotated -30 degrees on the Y axis and cut at 17.8mm on the Z axis. After a lot of experimentation I think this is probably the optimal cut to keep the model in as few parts as possible to print without supports. If you find something different, let me know!
Overall I'm quite happy with how it turned out! If you look closely at the top you'll see I had an issue with the top half lifting off the bed, causing a gap after I joined the pieces. I also definitely could have benefited from a vice / clamps when gluing pieces together.