Thanks Rich, worked perfectly!

Hi folks,

I'm experienced with AutoCAD but new to sketchup, I want to use a slicer plugin for sketchup to cut a google earth terrain into 3mm slices which can then be sent to a laser cutter to build a real life scale model.
The trouble is the google earth terrain is an irregular surface and the plugin needs it to be a solid.

What is the quickest/ easiest way to create a solid volume underneath the terrain surface?

Help much appreciated!

Thanks.