How to Use SketchUp’s Stamp Tool
Eventually, you may need to plunk down a building (or some other structure) on the terrain you’ve lovingly crafted in SketchUp. The Stamp tool provides an easy way to — you guessed it — stamp a building footprint into a terrain surface, creating a flat “pad” for something to sit on.
This tool also provides a way to create a gently sloping offset around the perimeter of your stamped form. This creates a smoother transition between the new, flat pad and the existing terrain.
Follow these steps to use the Stamp tool:
Move the building you want to stamp into position above your terrain surface.
The building shouldn’t touch the terrain but float in space directly above it. Also, turn the building into a group before you start moving anything.
If you’re having trouble moving your building into position accurately, move it to the correct height first and then switch to a top, no-perspective view to finish the job. Look in the Camera menu for both these commands.
Choose Tools→Sandbox→Stamp from the menu bar to activate the Stamp tool.
Click the floating object to tell SketchUp what you want to use as the stamp.
Type an offset distance and press Enter.
The offset distance is the amount of space around the perimeter of whatever you’re stamping that SketchUp uses to smooth the transition between the flat spot it’s creating and the existing terrain. The offset amount you choose depends entirely on what you’re stamping. Go nuts, and thank your lucky stars for Undo.
Move your cursor over your terrain surface and click again.
Move (but don’t drag) your mouse up and down to position the flat pad in space. Click again to finish the operation.
Here are a couple things that are handy to know when you use Stamp:
SketchUp uses the bottommost face in your stamp object as the template for the flat pad it creates in your terrain.
Stamp creates triangular faces that sometimes need cleaning.