Sketchup For Schools: How to build a Model Bridge truss
Sketchup can help you pre-visualize as you design a model bridge.
This video will demonstrate advanced use of the following techniques:
Making/Exploding Components
Moving/Duplicating objects
Moving/Duplicating/Multiplying objects
Rotation and locking the plane of rotation
It assumes that you're already familiar with drawing Rectangles and Lines, Push/Pull, Moving objects, and Orbiting/Navigating your workspace.