# 3D箭袋图像

演示在3d网格上的点处绘制方向箭头。

![3D箭袋图像示例](https://matplotlib.org/_images/sphx_glr_quiver3d_001.png)

```python
# This import registers the 3D projection, but is otherwise unused.
from mpl_toolkits.mplot3d import Axes3D  # noqa: F401 unused import

import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure()
ax = fig.gca(projection='3d')

# Make the grid
x, y, z = np.meshgrid(np.arange(-0.8, 1, 0.2),
                      np.arange(-0.8, 1, 0.2),
                      np.arange(-0.8, 1, 0.8))

# Make the direction data for the arrows
u = np.sin(np.pi * x) * np.cos(np.pi * y) * np.cos(np.pi * z)
v = -np.cos(np.pi * x) * np.sin(np.pi * y) * np.cos(np.pi * z)
w = (np.sqrt(2.0 / 3.0) * np.cos(np.pi * x) * np.cos(np.pi * y) *
     np.sin(np.pi * z))

ax.quiver(x, y, z, u, v, w, length=0.1, normalize=True)

plt.show()
```

## 下载这个示例
            
- [下载python源码: quiver3d.py](https://matplotlib.org/_downloads/quiver3d.py)
- [下载Jupyter notebook: quiver3d.ipynb](https://matplotlib.org/_downloads/quiver3d.ipynb)