The Glacier 2 Engine is IO Interactive's proprietary custom game engine designed to run Hitman games. What is known about the engine is a result of reverse-engineering the files provided to the community via the games themselves.
In order to understand the basics of Glacier 2 modding, there are a few core concepts to grasp. First, navigate to the Hitman 3 game directory.
Runtime folder contains files with the
rpkg file extension. These are the game's assets, listed in a set order and separated by chunks. For example,
chunk0 contains the global assets used in all of the game's missions. You can view what each chunk represents here.
Note: You may also notice chunk "patch" files corresponding to the chunk files. These are updates to the original files. You'll be using chunk patches to mod the game.
rpkg files contain unique asset types within them. Assets contained in these files have a hash (an alphanumeric sequence generated from the asset's name) and the asset data itself. You can view the different file formats names and their details here.
Asset data formats are diverse, but both readable and editable when using the proper tools. To make sense of these files, download the fittingly-named
rpkg tool here.1 Make sure you have the .NET Framework installed on your machine.
Also included in the
Runtime folder is a
packagedefinition.txt file. This file tracks the patches - updates and mod additions - to the game's content. The included file in a retail installation limits the amount of patches that the file can contain, so it itself also needs to be patched! You can find the patched version as well as a decoder and encoder here.
1Please, for the love of god, do not run the program directly from the ZIP file/7zip/whatever program you use.