Definiton: In computer graphics, back-face culling determines whether a polygon of a graphical object is drawn.

FFXIV handles this in a few different ways, and how you use them is up to your own taste.

Basics

Opening up a model, you can go into Viewport Overlays > Face Orientation.

This will show you some colors, depending on what way the normals are facing.

Blue: Single mesh layer, outward facing.

Red: Single mesh layer, inward facing.

Purple: Double mesh layer, with red under and blue on top.

Pink: Double mesh layer, with blue under and red on top.

How does FFXIV render this in-game?

It depends on your material “Backfaces” option!

Show Backfaces:

• Will show ALL faces. That means blue, red, pink and purple will always be showing.
• You do not want this if your mesh is pink and purple. It will look very funky because your normals will clip into each other.
• On a lot of meshes, blue and red will have slightly different looks. Generally you want anything that you see to be blue, because those are outwards facing normals.

Hide Backfaces:

• Will hide any inwards facing normals (backface culling). Red will be completely invisible, and pink/purple will look normal.