.. _sphx_glr_gallery_mplot3d_polys3d.py:


=============================================
Generate polygons to fill under 3D line graph
=============================================

Demonstrate how to create polygons which fill the space under a line
graph. In this example polygons are semi-transparent, creating a sort
of 'jagged stained glass' effect.




.. image:: /gallery/mplot3d/images/sphx_glr_polys3d_001.png
    :align: center





.. code-block:: python


    from mpl_toolkits.mplot3d import Axes3D
    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.)] + list(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()

**Total running time of the script:** ( 0 minutes  0.011 seconds)



.. only :: html

 .. container:: sphx-glr-footer


  .. container:: sphx-glr-download

     :download:`Download Python source code: polys3d.py <polys3d.py>`



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: polys3d.ipynb <polys3d.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.readthedocs.io>`_