# 生成多边形以填充3D线图

演示如何创建填充线图下空间的多边形。 在这个例子中，多边形是半透明的，产生一种“锯齿状的彩色玻璃”效果。

![生成多边形以填充3D线图示例](https://matplotlib.org/_images/sphx_glr_polys3d_001.png)

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

from matplotlib.collections import PolyCollection
import matplotlib.pyplot as plt
from matplotlib import colors as mcolors
import numpy as np

# Fixing random state for reproducibility
np.random.seed(19680801)


def cc(arg):
    '''
    Shorthand to convert 'named' colors to rgba format at 60% opacity.
    '''
    return mcolors.to_rgba(arg, alpha=0.6)


def polygon_under_graph(xlist, ylist):
    '''
    Construct the vertex list which defines the polygon filling the space under
    the (xlist, ylist) line graph.  Assumes the xs are in ascending order.
    '''
    return [(xlist[0], 0.), *zip(xlist, ylist), (xlist[-1], 0.)]


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

# Make verts a list, verts[i] will be a list of (x,y) pairs defining polygon i
verts = []

# Set up the x sequence
xs = np.linspace(0., 10., 26)

# The ith polygon will appear on the plane y = zs[i]
zs = range(4)

for i in zs:
    ys = np.random.rand(len(xs))
    verts.append(polygon_under_graph(xs, ys))

poly = PolyCollection(verts, facecolors=[cc('r'), cc('g'), cc('b'), cc('y')])
ax.add_collection3d(poly, zs=zs, zdir='y')

ax.set_xlabel('X')
ax.set_ylabel('Y')
ax.set_zlabel('Z')
ax.set_xlim(0, 10)
ax.set_ylim(-1, 4)
ax.set_zlim(0, 1)

plt.show()
```

## 下载这个示例
            
- [下载python源码: polys3d.py](https://matplotlib.org/_downloads/polys3d.py)
- [下载Jupyter notebook: polys3d.ipynb](https://matplotlib.org/_downloads/polys3d.ipynb)