3D Line Spiral Plot

Mix.install([
  {:plotly_ex, "~> 0.3"},
  {:kino, "~> 0.18"}
])

Section

Setting line.color to a numeric list (same length as x/y/z) + line.colorscale: colors the line by a variable — here z-position. This creates a gradient spiral showing how the line progresses through space.

alias Plotly.{Figure, Scatter3d}

n = 300
t = Enum.map(0..(n - 1), &(&1 / (n - 1) * 10 * :math.pi()))
x = Enum.map(t, &:math.cos/1)
y = Enum.map(t, &:math.sin/1)
z = Enum.map(t, & &1)

Figure.new()
|> Figure.add_trace(
  Scatter3d.new(
    x: x,
    y: y,
    z: z,
    mode: "lines",
    line: %{
      color: z,
      colorscale: "Viridis",
      width: 4
    }
  )
)
|> Figure.update_layout(
  title: "3D Line Spiral — Color by Z",
  scene: %{
    xaxis: %{title: "X"},
    yaxis: %{title: "Y"},
    zaxis: %{title: "Z"}
  }
)
|> Plotly.show()