[header] How to create contour lines using sketchup [title] Click on the add imagery icon. [step] Go to wherever you want to get your contours from in the screen that comes up. [title] Draw a rectangle that is the size of the contours that you are creating. 
[title] Click on the move tool and holding down ctrl and make a copy and make sure it is directly above the previous layer. [step] Type in the number that you want for contour lines.