It works around weight painting issues in certain chest pieces by over-scaling the chest bones. Yes it's a giant hack but it works without modifying the gear models themselves. This is accomplished via my plugin [Refitter]({{< ref "refitter" >}}).
{{<blurbtitle="Download Configuration"description="Download the NARC configuration."url="https://xiv.zone/distrib/narc/config.json">}}
{{<blurbtitle="Download Penumbra Mod"description="Download the Penumbra mod (optional) to fix clipping with some armor."url="https://xiv.zone/distrib/narc/narc-penumbra.zip">}}
[VARC](/mods/varc) does the same thing, but through manually fixing the weight painting on the gear model themselves. While this works (assuming I fixed it, and not making it worse) it's very time consuming.
A secondary and less important reason is to prevent breakages during game updates. Previously, VARC depended on Penumbra to update first. And now with the graphical update ongoing, gear models could be changed from underneath us!
Refitter is much simpler to update in comparison, and NARC needs no updates itself unless any gear's weight painting changes.
### Can I selectively apply this to certain characters?
I have no plans to build that feature into Refitter at the moment.
### What is the difference between Refitter and NARC?
Refitter is the Dalamud plugin I created to modify the chest bones, it technically has nothing to do with NARC. NARC is just a configuration file for it I've been tweaking.