add README.md

README.md

@@ -39,7 +39,11 @@ If you use this data, please cite the original authors:
 This release ships archives. Extract them in-place before pointing `SPATIAL_DATA_HOME` at this directory:
 
 ```bash
-cd 2D/; for f in *.tar; do tar -xf $f; done; cd ../3D/; for f in *.tar; do tar -xf $f; done
+# Reassemble multipart archives, then extract
+cat 2D/depth/depth.tar.gz.part_* > 2D/depth/depth.tar.gz
+cat 2D/image/image.tar.gz.part_* > 2D/image/image.tar.gz
+cat 3D/image_visual_choice/image_visual_choice.tar.gz.part_* > 3D/image_visual_choice/image_visual_choice.tar.gz
+find . -name '*.tar.gz' -execdir tar -xzf {} \;
 ```
 
 ## Usage in Molmo2-ER