   world editor brush
  what is a brush in a world editor and what does it do? 
  AFAIK it''s a rather silly and unintuitive name for a bit of primitive geometry. (cube, pyramid, sphere etc)Now you know that, their use should be pretty obvious. i.e you build the level out of them. ;  Yeah, it is kinda non-intuitive. But the roots go back to simple image editors (and even Real LifeTM) in which various paintbrushes are used to apply colors in an image. Extend that idea to a paintbrush that instead of just applying color, applies terrain elements, objects, etc... and you have the idea.Depending on how extensive the editor is, you can have many types of brushes. A terrain-type brush would merely be an arbitrary sized location of ground that follows the mouse cursor, and applies terrain of the selected type to that area (grass, dirt, rock, whatever). An elevation brush would be a location that follows the mouse and modifies terrain elevation up or down, depending on settings, to make hills or canyons. A tree/forest brush could be used to apply large swathes of forest, and have customizable tree-type and tree-density settings. And so on. Just think "complicated paintbrush" and you''ll be alright.   GolemBlender--The Gimp--Python--Lua--SDLNethack--Crawl--ADOM--Angband--Dungeondweller