Halo 3’s forge mode – the game’s editing suite – is in for a serious revamp when Halo: Reach is released in September.
As Mike saw earlier today at Comic-Con, Halo: Reach has replaced Forge with Forge World, a vastly improved editing tool that not only lets players craft much larger maps, but also have a much more detailed method of interacting with them.
https://kotaku.com/halo-reachs-new-firefight-covenant-mode-forge-world-5594250
As an example, there will be multiplayer maps shipping on Reach’s disc that were created using only Forge World. And that’s from a dev team under crunch to get a game shipped. When the community get their hands on it, I expect amazing things to happen.