UDIM Tiles & Metallic/Roughness Options

Two checkboxes in the Transfer Texture panel control how Export Mesh writes textured materials out, independent of how they're baked internally.

Export UDIM tiles

On: Export Mesh writes one texture page per UDIM tile beside the model (<asset>_albedo.1002.png, and so on) and gives the whole mesh a single material referencing them through one <UDIM> path — the convention Maya, Mari, Substance, Houdini and Blender all expand per tile. Off — or exporting to glTF/GLB, which has no UDIM concept and always overrides this — each tile is written as its own material with its own texture instead. A model whose UVs all sit in one tile exports identically either way.

UDIM tile assignment itself (the UV Tile Manager) is a Regular and up capability — in Free and Light every material always answers tile 1001, so this checkbox is present everywhere but has nothing to do there.

Metallic and Roughness are separate

On by default: Export Mesh writes Metallic and Roughness as two standalone greyscale textures — how FBX and most other formats actually carry them, and likely how the source model was authored. Vertexix always bakes and previews internally as one combined map regardless of this checkbox; it only changes what gets written out. Off packs them into one glTF-style combined texture instead (green channel = roughness, blue = metallic) — turn this off specifically when exporting to glTF or GLB, the one format that requires them packed and ignores the checkbox either way to enforce it.

FBX is the format this checkbox mainly exists for: its material model has no metallic/roughness channel at all, so every consuming PBR pipeline (Substance Painter, Unreal, Blender) matches textures by filename convention — exactly what split output produces.