[quote][b]Posted by:[/b] Eric Duffy [quote][b]Posted by:[/b] funkbrotha10 [/quote] But only Bungie has it.[/quote]They've built proprietary tools that probably have much more advanced or specialized features in comparison to similar commercial development software. For instance, Grognok probably has more specialized tools than something like Adobe Mudbox when it comes to sculpting an environment from a plane for the purposes of exporting a heightmap. They might also need special tools to manage items in their library of assets in whatever unique way they do it. Also, it would most definitely be customized to handle filetypes specific to their engine that other software simply doesn't support.