Multiple 3D Cone

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

Section

Multiple Cone traces can be combined on the same scene — useful for comparing two vector fields or showing field lines at different scales. Each trace has its own colorscale: and sizeref:. Setting showscale: false on all but one avoids cluttering the color bar.

alias Plotly.{Figure, Cone}

# Field 1: rotation around z-axis (z=0 plane)
pos1 = for x <- [-1, 0, 1], y <- [-1, 0, 1], do: {x, y, 0}
x1 = Enum.map(pos1, &elem(&1, 0))
y1 = Enum.map(pos1, &elem(&1, 1))
z1 = List.duplicate(0, length(pos1))
u1 = Enum.map(y1, &(-&1))
v1 = Enum.map(x1, & &1)
w1 = List.duplicate(0, length(pos1))

# Field 2: diverging field (radially outward) at z=2
pos2 = for x <- [-1, 0, 1], y <- [-1, 0, 1], do: {x, y, 2}
x2 = Enum.map(pos2, &elem(&1, 0))
y2 = Enum.map(pos2, &elem(&1, 1))
z2 = List.duplicate(2, length(pos2))
u2 = x2
v2 = y2
w2 = List.duplicate(0, length(pos2))

Figure.new()
|> Figure.add_trace(
  Cone.new(x: x1, y: y1, z: z1, u: u1, v: v1, w: w1,
           colorscale: "Blues", sizeref: 0.4, showscale: true, name: "Rotational")
)
|> Figure.add_trace(
  Cone.new(x: x2, y: y2, z: z2, u: u2, v: v2, w: w2,
           colorscale: "Reds", sizeref: 0.4, showscale: false, name: "Diverging")
)
|> Figure.update_layout(
  title: "Multiple 3D Cone Traces",
  scene: %{
    xaxis: %{title: "X"},
    yaxis: %{title: "Y"},
    zaxis: %{title: "Z"}
  }
)
|> Plotly.show()