Collection structure
The structure is the central data model of Blending to Unreal. It gives each asset a predictable set of typed collections and validation rules.
Collections created
For an asset named Rock_A, Create Structure creates the Main collection Rock_A and typed child collections using the asset name as a prefix.
| Type | Purpose |
|---|---|
| Parent | Contains exactly one generated Parent Empty; exportable geometry is expected to be parented to it. |
| LOD0–LOD7 | Static-mesh geometry for each LOD level. LOD0 must exist and contain geometry; active LODs must form a valid sequence. |
| SOCKET | Socket helper objects exported with the asset. |
| UBX / UCP / USP / UCX | Simple Unreal collision geometry. |
| ComplexCollision | Dedicated geometry for complex collision export. |
| Asset | Hidden, asset-marked wrapper with LOD instance Empties used for reusable placement. |
| Dump | Helper collection excluded from ordinary asset geometry output. |
Validation rules
Validate Structures checks structural assumptions before export. Among other rules, the current code expects:
- The Main collection does not directly contain objects.
- Parent contains exactly one Empty and that Empty has scale 1,1,1.
- LOD0 contains geometry and active LOD indices form a valid sequence.
- Objects in relevant typed collections are parented to the Parent Empty.
- LOD materials have no empty slots, material names contain no dot, and the Unreal target material field is populated.
- The generated Asset wrapper exists, is hidden from render/viewport, marked as an asset and contains exactly one Empty instance per available LOD.
Refresh & rename
Refresh Structure restores canonical collection names, initializes LOD screen-size metadata, repairs parent relationships for complex collision geometry and rebuilds the generated Asset wrapper. It refuses ambiguous structures with missing/duplicate typed collections or untagged direct children.
Rename Structure renames the Main collection and restores every typed child name to the new base name. Existing LOD collection instances are also renamed.
Legacy conversion
Convert from Legacy exists for older structure layouts. Use it when a file was created by the previous structure convention rather than manually retagging collections.