So you must use Plugins of Fredo Joint PushPull, Curviloft Shape bender by Chris Fullmer... http://www.youtube.com/watch?v=tGHTIOMm_34 http://www.youtube.com/watch?v=holafltwWrc http://www.youtube.com/watch?v=qsKZpmrJkxs or this one (there a free version! Minute 3.50 http://www.youtube.com/watch?v=UviJRlu_00w Or use intensively the SketchUp native tool: Sand Box