add dataset card with explicit CC BY 4.0 licensing

README.md

@@ -58,9 +58,12 @@ configs:
 A Hugging Face packaging of the **Amazon Berkeley Objects (ABO)** dataset. The
 data content is the official CC BY 4.0 release from
 <https://amazon-berkeley-objects.s3.amazonaws.com/index.html>. This mirror
-changes only the packaging: metadata and media are grouped into typed Parquet
-shards using the `datasets` `Image()` and `Mesh()` features so the Hugging Face
-Dataset Viewer and `datasets` streaming APIs can consume them.
+changes only the packaging: files are grouped into typed Parquet shards, and
+**every original media file is preserved byte-for-byte and never transcoded**.
+Images use the `datasets` `Image()` feature, 3D product models use the native
+`Mesh()` feature (original GLB bytes), and part-label meshes are kept in their
+original `.obj` format — so the Hugging Face Dataset Viewer and `datasets`
+streaming APIs can consume them.
 
 ## Configs
 
@@ -72,12 +75,16 @@ Dataset Viewer and `datasets` streaming APIs can consume them.
 | `images_original` | One catalog image | Original-resolution `Image()`, dimensions, path |
 | `spins` | One turntable frame | `Image()`, `spin_id`, `image_id`, `azimuth` |
 | `models_3d` | One 3D product | Native `Mesh()` GLB and geometry/material stats |
-| `part_labels` | One part mesh | Byte-exact `source_obj` plus converted `Mesh()` GLB |
+| `part_labels` | One part file | Original `.obj` part-mesh bytes (verbatim) or `relation.json`; keyed by `item_id`/`part_id` |
 | `benchmark_material` | One model-viewpoint file | Render/material `Image()` or EXR `blob`, `kind` |
 | `mvr` | One retrieval example | Official CVPR22 multi-view-retrieval split columns |
 
-Native 3D preview uses the `Mesh()` feature and requires a recent `datasets`
-release with mesh support.
+`models_3d` uses the native `Mesh()` feature (requires a recent `datasets`
+release with mesh support). Part-label meshes are stored in their original
+`.obj` format under `part_labels`, alongside each item's `relation.json`. Note:
+the Hugging Face **Dataset Viewer does not yet render the `Mesh` feature**; 3D
+models can still be previewed via the Hub's per-file viewer and loaded through
+`datasets`.
 
 ## Licensing