HELLLLLLLP! Model Lost is UCS

Someone please help! I was placing a line in my model and did something with the UCS, then all the sudden all of these blue lines appeared, orbitting around and then my model completely disappeared! I tried to adjust the views and reset the UCS but I still cannot locate any of the 3D solids that I have spent 17 hours working on! I tried opening up the backup file and it is not working. Does someone know what has happened????

Your first reaction should have been something other than opening up the backup file. How about UNDO? Or how about quitting out of the drawing WITHOUT saving it. Is AutoCAD functional? Can you open any other 3D drawing without a problem? Not sure what blue lines you're referring to or where they may have come from unless you were doing a Revolve. Were you?

if you select all (ctrl+A), does it find something? If it does you can use Zoom-Object to zoom to it.

try using the following comands: hit the z button, hit enter, hit a, hit enter, this should move the zoom to where the entire model will fit in the screen

to open the backup file change the .bak to .dwg.