docs/storage_spec.md

# Asset Storage Specification

## Canonical path

```text
assets/<source>/raw/<asset_type>/<category>/<asset_id>/
```

For large upstream trees that rely on many relative references, use the same four-level layout and store the upstream tree inside the collection asset directory:

```text
assets/<source>/raw/<asset_type>/<category>/<asset_id>/
```

In that case, keep the upstream directory layout intact inside the collection directory and index the collection with a root `metadata.yaml`.

Example:

```text
assets/discoverse/raw/collections/models/discoverse_models/
├── metadata.yaml
├── mjcf/
├── meshes/
└── urdf/
```

## Derived assets

Generated or transformed outputs must not overwrite raw assets. Store them under:

```text
assets/<source>/derived/<asset_type>/<category>/<asset_id>/
```

Use this for:

- convex decomposition results
- primitive collision proxies
- collision-only meshes
- format conversions
- normalized or cleaned variants

If a derived asset keeps a direct dependency on a raw asset, reference the raw asset in metadata and preserve provenance links.

Current derived collision asset types:

```text
assets/<source>/derived/convex_decompositions/<category>/<asset_id>/
assets/<source>/derived/primitive_collision_proxies/<category>/<asset_id>/
```

Convex decomposition details are in:

```text
docs/convex_decomposition_spec.md
```

Primitive collision proxy details are in:

```text
docs/primitive_collision_proxy_spec.md
```

## Required per-asset files

- Source asset files, preserving upstream structure where practical.
- `metadata.yaml`.

If a source is reorganized during import, also record the upstream-to-local structure mapping in:

```text
docs/structure_mapping.md
docs/source_notes/<source>.md
```

## Global index

All assets must be indexed in:

```text
manifest/assets.jsonl
```

Use one JSON object per line.

## MJCF assets

For MuJoCo/MJCF assets:

- `model.xml` is the preferred entry file.
- Meshes and textures should remain relative to `model.xml`.
- Common mesh formats: `.obj`, `.stl`, `.dae`.
- Common texture formats: `.png`, `.jpg`, `.jpeg`.

Example:

```text
assets/robocasa/raw/fixtures/dishwashers/Dishwasher031/
├── metadata.yaml
├── model.xml
└── visuals/
    ├── Body001.obj
    └── T_BC001.png
```