3D Mesh Tetrahedron

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

Section

When i:, j:, k: are provided, Mesh3d uses explicit triangle face connectivity instead of computing faces from the point cloud. Each element of i/j/k is a 0-based vertex index; the three together define one triangular face. A tetrahedron has 4 vertices and 4 faces.

alias Plotly.{Figure, Mesh3d}

Figure.new()
|> Figure.add_trace(
  Mesh3d.new(
    # 4 vertices of a tetrahedron
    x: [0, 1, 2, 0],
    y: [0, 0, 1, 2],
    z: [0, 2, 0, 1],
    # 4 triangular faces (indices into x/y/z)
    i: [0, 0, 0, 1],
    j: [1, 2, 3, 2],
    k: [2, 3, 1, 3],
    # per-face or per-vertex intensity for coloring
    intensity: [0, 0.33, 0.66, 1.0],
    colorscale: "Viridis",
    opacity: 0.7
  )
)
|> Figure.update_layout(
  title: "Tetrahedron — Explicit Face Connectivity",
  scene: %{
    xaxis: %{title: "X"},
    yaxis: %{title: "Y"},
    zaxis: %{title: "Z"}
  }
)
|> Plotly.show()