Daz is giving away Hexagon (again) but the plus is that it actually works now.. (at least on the mac it is for me, which is new) 

 

Much of the current carrara vertex modeling system was ported from hex.. go get it, give it a try...

 

http://www.daz3d.com/i/3d/free-3d-software-overview?

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Hexagon, Carrara, Sculptris, and recently Sketchup.