3d Engineers lets you create constructions and mechanics in a physics environment.
Combine simple materials like beams, ropes, hydraulics, rockets aso to build architecture or vehicles from the ground up. Middle age or space is no topic as you are the inventor.
This game is beeing constantly extended, improved and updated.

3d Engineers is coming with the full version of -3d.Bridges- (avaiable on Steam as well)
35 Leveltasks
8 Tutorial levels
8++ Playground levels