The Halo Editing Kit is a comprehesive collection of tools and tutorials for how to make and distribute custom content and maps for the Halo Custom Edition game.
There are several components of the Halo Editing Kit - each has a separate function.
Sapien is one of the major tools in the HEK. Sapien is the easiest tool to use, although you cannot make a map solely by Sapien. Sapien features several windows: the game view, which is the 3d illustration of the camera. You can move it the the normal HCE flycam controls; the hierarchy view, which lists objects, AI, weapons, vehicles, etc. on the map; the tool window, which mainly edits other things that apply to general objects; the property window, which displays the properties of the object(s) selected in the hierarchy view; and finally the output window, which, obviously, displays the output. It is by using this tool, you can place, rotate and populate the map with spawn points, weapons and the like. Essentially, it is a sort of Forge.
Guerilla is a text heavy application that comes with the HEK. It's primary function is for creating and editing tags, which are the elements of everything that makes up the maps. Although it can be confusing, there are multiple tutorials explaining the functions of all the tags and what Guerilla can do to them.
Tool is a console-based application which requires command prompt to function. It is only really used to compile and convert filetypes relevent to Halo map making, like turning a 3D landscape into a map landscape for Halo to use, as well as the final compiling of all the tags into the final product, the map itself. There are explanations to errors that can occur across the Internet, so a solution to any issue is usually only a Google search away.
Add-ons and AlternativesEdit
While the normal tools are generally enough, some things cannot be achieved by normal means and tools, even though the engine and game is entirely capable of supporting it.
This 3rd party program was developed by Kornman00 to extend the engine and increase it's functionality, ability and open oppotunities for new concepts that the game couldn't achieve before. While it is great for giving content creators new toys to play with and generally beautifying the game, it hasn't been adopted by some due to it's additional PC effort demand that it draws to add the post processing. It has recieved a generally postive responce overall though.