Custom mesh flag integration

Nation Flag System swaps nations by setting MeshPart.TextureID. Custom draped / hanging flag meshes work as long as the cloth surface is a MeshPart and its UVs expect a rectangular flag image.

If you use SurfaceAppearance, Decals, or Texture instances instead, this path will not drive them — stick to TextureID on the mesh.

What the registry looks for

Each pole is a Model. FlagRegistry picks one MeshPart inside it:

1. Prefer a descendant whose name contains flag (case-insensitive), e.g. Meshes/flagpiece (1)
2. Else the first MeshPart that already has a non-empty TextureID
3. Else the first MeshPart in the model

A ProximityPrompt named FlagChangePrompt is parented to that mesh.

Model layout

Workspace.Flags                -- or Config.FlagFolderPath
└── MyDelegatePole (Model)     -- optional: CollectionService tag CustomizableFlag
    ├── Pole (Part)            -- geometry only; ignored for textures
    └── Meshes/flagpiece (1) (MeshPart)   -- TextureID is swapped here

Outside the flags folder, tag the Model CustomizableFlag (see Config.CollectionTag).

TextureID requirements

When a nation is applied, the server writes roughly:

mesh.TextureID = "http://www.roblox.com/asset/?id=" .. assetId

So:

Requirement	Why
Target is a MeshPart	Only TextureID is updated
No SurfaceAppearance on that mesh	SurfaceAppearance overrides / ignores TextureID
Mesh UVs map a full rectangle across the cloth	Catalog flags are rectangular images
Asset is a Roblox Image (AssetType Image)	Same as typical flag decals / textures

You can seed a default look by setting TextureID in Studio before play; the prompt ObjectText will reverse-match known catalog textures when possible.

UV tips for custom cloth meshes

• Author UVs so the entire flag face uses 0–1 UV space (one nation image fills the cloth).
• Avoid packing pole/hardware into the same UV island as the flag — those pixels will show flag colors when swapped.
• Square vs wide flags: most catalog assets are wider than tall; hanging meshes that compress horizontally still work, but emblems may look squeezed.
• Double-sided cloth: one MeshPart with both sides sharing UVs is fine; two meshes need both named with flag or only one will update.

Checklist

1. Build or import your flag as a MeshPart
2. Put it under a Model (pole + flag)
3. Name the cloth mesh with flag in the name
4. Parent the Model under Workspace.Flags or tag CustomizableFlag
5. Confirm there is no SurfaceAppearance on the cloth mesh
6. Play, use the prompt, pick a nation — TextureID should change on the mesh

Verifying in Studio

Select the cloth MeshPart after a successful change:

• TextureID should contain the new asset id
• Model attribute CurrentNation should be the nation id (e.g. US, UNO)
• Prompt ObjectText should show the nation display name

If the prompt works but the mesh does not visually update, almost always: wrong mesh selected, SurfaceAppearance present, or UVs not on the visible cloth.