def point_cloud_three_views(points):
    """ input points Nx3 numpy array (+y is up direction).
        return an numpy array gray image of size 500x1500. """
    # +y is up direction
    # xrot is azimuth
    # yrot is in-plane
    # zrot is elevation
    img1 = draw_point_cloud(points, zrot=110 / 180.0 * np.pi, xrot=45 / 180.0 * np.pi, yrot=0 / 180.0 * np.pi)
    img2 = draw_point_cloud(points, zrot=70 / 180.0 * np.pi, xrot=135 / 180.0 * np.pi, yrot=0 / 180.0 * np.pi)
    img3 = draw_point_cloud(points, zrot=180.0 / 180.0 * np.pi, xrot=90 / 180.0 * np.pi, yrot=0 / 180.0 * np.pi)
    image_large = np.concatenate([img1, img2, img3], 1)
    return image_large
 input points Nx3 numpy array (+y is up direction).
        return an numpy array gray image of size 500x1500. 
visualizer/pc_utils.py