def render_ground(self, size=[20.0, 20.0],
                  dsize=[1.0, 1.0],
                  color=[0.0, 0.0, 0.0, 1.0],
                  line_width=1.0,
                  axis="y",
                  origin=True,
                  use_arrow=False,
                  lighting=False):
    if self.ground_node is None:
        lx = size[0]
        lz = size[1]
        dx = dsize[0]
        dz = dsize[1]
        nx = int(lx / dx) + 1
        nz = int(lz / dz) + 1

        grid_pts = np.zeros((2 * nx + 2 * nz, 3))
        colors = np.zeros((2 * nx + 2 * nz, 4))
        colors[:] = np.array(color)

        if axis is "x":
            linei = 0
            for i in np.linspace(-0.5 * lx, 0.5 * lx, nx):
                grid_pts[2 * linei] = [0, i, -0.5 * lz]
                grid_pts[2 * linei + 1] = [0, i, 0.5 * lz]
                linei += 1
            for i in np.linspace(-0.5 * lz, 0.5 * lz, nz):
                grid_pts[2 * linei] = [0, -0.5 * lx, i]
                grid_pts[2 * linei + 1] = [0, 0.5 * lx, i]
                linei += 1
        elif axis is "y":
            linei = 0
            for i in np.linspace(-0.5 * lx, 0.5 * lx, nx):
                grid_pts[2 * linei] = [i, 0, -0.5 * lz]
                grid_pts[2 * linei + 1] = [i, 0, 0.5 * lz]
                linei += 1
            for i in np.linspace(-0.5 * lz, 0.5 * lz, nz):
                grid_pts[2 * linei] = [-0.5 * lx, 0, i]
                grid_pts[2 * linei + 1] = [0.5 * lx, 0, i]
                linei += 1
        elif axis is "z":
            linei = 0
            for i in np.linspace(-0.5 * lx, 0.5 * lx, nx):
                grid_pts[2 * linei] = [i, -0.5 * lz, 0.]
                grid_pts[2 * linei + 1] = [i, 0.5 * lz, 0.]
                linei += 1
            for j, i in enumerate(np.linspace(-0.5 * lz, 0.5 * lz, nz)):
                grid_pts[2 * linei] = [-0.5 * lx, i, 0.]
                grid_pts[2 * linei + 1] = [0.5 * lx, i, 0.]
                linei += 1
        grid = pyrender.Primitive(grid_pts, color_0=colors, mode=1)  # 1->LINES
        grid = pyrender.Mesh([grid])
        self.ground_node = Node(mesh=grid, name="ground_plane")
        self.scene.add_node(self.ground_node)