---
license: apache-2.0
---

## FlowOcc3D (flow dataset)

Download [FlowOcc3D](https://drive.google.com/file/d/1Xo2A40bUYA1wwXxqi_y6sQqu5mRRkc-s/view?usp=sharing). Unzip it in `./data/nuscenes`.

Here we briefly introduce what the downloaded file looks like. We store the flow and index of the foreground voxels in the `.bin` file and the `_idx.bin` file.
```python
W, H, Z = 200, 200, 16
sample_idx = results['sample_idx'] # nuScenes sample token
data_path = os.path.join('./data/nuscenes', 'occ_flow_sparse_ext', sample_idx)

occ_flow = np.ones((W*H*Z, 2)) * pad_value # pad_value could be zero
sparse_flow = np.fromfile(data_path + '.bin', dtype=np.float16).reshape(-1, 3)[:, :2]
sparse_idx = np.fromfile(data_path + '_idx.bin', dtype=np.int32).reshape(-1)
occ_flow[sparse_idx] = sparse_flow
occ_flow = occ_flow.reshape(W, H, Z, 2)