Understanding the Methodology Behind Starfield 1.11.33 Mesh Migration Tool

Introduction:
Bethesda's recent update to Starfield version 1.11.33 brought significant changes to the mesh files used in the game. While the naming convention for mesh files remained consistent, the contents of all meshes were modified. Consequently, the SHA1 hash of each mesh file changed, leading to new filenames for all meshes. This update presented challenges for modders who relied on these files in their creations, prompting the development of a tool to assist in remedying the situation.

The Issue:
The core challenge stemmed from how Bethesda stores mesh files. Utilizing the SHA1 hash of the mesh file contents as the folder and filename ensures consistency and integrity. However, with the 1.11.33 update, modifications to all mesh files altered their contents, resulting in new filenames for each mesh. While vanilla NIF files were updated to reflect these changes, mods referencing vanilla meshes suddenly found themselves without the necessary mesh files.

The Process:
To address this issue, I devised a methodology to create a mapping file that links the old mesh names to the new ones. Here's a step-by-step breakdown:


1. Scan Vanilla NIF Files: The first step involved scanning all vanilla NIF files to collect data such as file paths, geometry object names, LOD numbers, and mesh paths. This data was stored in a database.

2. Repeat for Old and New NIFs: The scanning process was repeated for both the old and new versions of the NIF files.

3. Eliminate Duplicates: The collected data was grouped by (NIF file name, object name, LOD number), and duplicates were eliminated to ensure uniqueness.

4. Join Tables: The tables containing data from the old and new NIF files were joined, retaining only the old and new mesh paths.

5. Resolve Duplicates: Any duplicates in the resulting table were resolved by ensuring that each old mesh path corresponded to only one new mesh path.

6. Export Data: Finally, the resolved data was exported to a colon-separated key-value pairs format, creating a data file that could be used to fix NIF files.

Conclusion:
This methodology provided a systematic approach to address the mesh migration issue introduced by the Starfield 1.11.33 update that can be applied with each new release.