Federation L-Type Cruiser. All credit for the 3D model goes to Jay Thurman (cyberia23) - see link for more details:
https://3dwarehouse.sketchup.com/collection.html?id=d1eb273facd30bfcdd821470ed8efdff
Cm:0.608 x / 3.178 y / 2.7 z
Note: this model printed well in WSF for me, but had a few minor glitches on one side - I filled it with a bit of milliput and it looks great now