Contour Lines vs. Reality. As reliable as a topographic map might be, it can’t reveal every detail of the terrain. A 20-foot-high cliff or a 30-foot deep ditch could exist between two 40-foot ...

SketchUp Tip: Creating 3D contour lines for do-it-yourself topo maps. August 24, 2012. Here’s a great little SketchUp video tutorial from the folks at concept3D, ...