Garage games have recently completed work on their Constructor tool, which they've been working on for the last 2 years.. which is released for Free! I've not used it yet, but as Torque uses csg for its interiors, and as constructor exports to .map format, it might be worth a look into before we go off down the reinvent the wheel road

Here are some CSG editors, some free, some commercial..

Cartography Shop: http://cartographyshop.thegamecreators.com/
3D World Studio: http://3dworldstudio.thegamecreators.com/
Quark: http://quark.planetquake.gamespy.com/
Hammer: http://games.softpedia.com/get/Tools...r-Editor.shtml
Constructor: http://www.garagegames.com/products/torque/constructor/

so why on earth would we want to write another one?... :lol: