Wanted to experiment and try building an internal spiral tunnel. I started by making the slope 1.1 degrees. I then start making a large spiral (covered 4 bases). When I got it to about 200 meters, I stopped and enclosed it in the ground by raising the land all around it. No problem. My next thought was to have bridge go across a valley into another tunnel and then make another spiral tunnel going even higher. As soon as I started the second spiral, CTD. Ok....maybe it didn't like being that high. So, I raised the land where the second mountain would be to 200 meters and tried again. Got about one turn made and it crashed again. Multiple attempts after that got me nowhere.
Any ideas?
Any ideas?