HOW TO CREATE TERRAIN IN SKETCHUP WITH SANDBOX TOOL

Sandbox tool used to build terrain in sketchup includes the following functions:
From Contours: create contour contours from imported cad files.
From Scratch : create terrain by drawing a rectangular grid.
Smoove: create convexity for the terrain created by the two functions above.
Stamp : flatten the terrain by the perpendicular projection of a flat block
located above that terrain.
Draw : print the projection of a plane onto the terrain with contours
of the plane will contour along the slope of that terrain.
Add Detail : increase the density of grid cells to make the terrain smoother.
Flip Edge : flip the diagonal grid lines as desired.