Plot

Plot is an Obsidian plugin for creating interactive 2D graphs and 3D surfaces directly in your notes.

Features

• Plot equations as 2D curves or 3D surfaces.
• Render 3D scenes with WebGL; generate meshes in a background worker, with Canvas2D fallback.
• Choose wireframe, solid-surface, or point-cloud rendering.
• Add points, vectors, and adjustable variables.
• Visualize 2D/3D vector fields with normalized arrows and adjustable sampling density.
• Define 3D piecewise surfaces with one equation and condition per branch.
• Group equations into systems and choose which equations, intersections, and approximate solutions to show.
• Configure keyboard zoom, panning, reset, and movement steps in plugin settings.
• Render inline LaTeX in labels with $...$ delimiters.
• Change the camera, axes, grid, resolution, and intersection display.
• Edit a graph through the visual controls or directly in its JSON code block.
• Evaluate expressions with a restricted mathematical parser.

Install

Download main.js, plot-worker.js, manifest.json, and styles.css from a release and place them in your vault at:

<Vault>/.obsidian/plugins/plot/

Restart Obsidian if needed, then enable Plot under Settings > Community plugins. The release may also include prompt.md; it is not required to load the plugin.

Use

Run Create new graph (Modal UI) from the Command palette, or add a math-plot code block to a note. For example:

```math-plot
{
  "type": "3d",
  "renderStyle": "wireframe",
  "resolution": 50,
  "axisMode": "ticks",
  "items": [
    {
      "type": "var",
      "name": "x0",
      "value": 1.5,
      "min": -3,
      "max": 3,
      "step": 0.1
    },
    {
      "type": "fn",
      "fn": "4 - 0.25 * x^2 - 0.25 * y^2",
      "color": "#e91e63",
      "opacity": 0.7,
      "label": "Paraboloid"
    },
    {
      "type": "point",
      "coords": "x0, 0, 4 - 0.25 * x0^2",
      "color": "#ff9800",
      "label": "P"
    }
  ]
}
```

Use "type": "2d" for a 2D graph. In 3D, bounds is [xMin, xMax, yMin, yMax]; in 2D, it is [xMin, xMax]. Point coordinates and vector origins/directions are comma-separated expressions and can use declared variables.

Vector fields

Use vectorField with two components in 2D or three in 3D. Arrows are normalized so direction remains readable; density controls the sample count per axis (3–16, default 6).

{
  "type": "2d",
  "items": [
    { "type": "vectorField", "components": "-y, x", "density": 8, "color": "#00e676", "label": "$\\vec F$" }
  ]
}

Piecewise surfaces

In 3D, each piecewise branch contains an explicit equation such as x + y (interpreted as z = x + y) or an implicit equation such as x^2 + y^2 + z^2 = 1, plus a boolean condition over x, y, and z. Comparisons (<, <=, >, >=, =, !=) and and/or are supported; common LaTeX commands include \\leq, \\geq, \\land, and \\lor. The editor can switch between branch rows and a \\begin{cases}...\\end{cases} representation.

{
  "type": "3d",
  "items": [
    {
      "type": "piecewise",
      "branches": [
        { "equation": "x + y", "condition": "z >= 0" },
        { "equation": "x - y", "condition": "z < 0" }
      ]
    }
  ]
}

Systems

Use a system item to group equations. Each equation has its own visibility checkbox; intersections and solution markers are independently switchable. In 2D, equations are explicit curves (y = f(x)). In 3D, use explicit surfaces (z = f(x,y)) or implicit surfaces (F(x,y,z) = 0). The editor also supports a \\begin{aligned}...\\end{aligned} LaTeX representation.

Intersection and solution calculations are numerical and bounds-limited. The 2D solver samples explicit curves; the 3D solution marker solver uses multistart Newton iteration and requires at least three equations. These methods may miss tangencies or roots, and do not guarantee uniqueness or completeness. 3D intersection curves are currently calculated for explicit surfaces; implicit surfaces can still be visualized and used for isolated solution markers.

Keyboard navigation defaults to =/- for zoom, arrow keys for panning, and 0 to reset. Bindings and zoom/pan steps are configurable under Settings > Plot; shortcuts act only while the plot is focused or under the pointer.

Supported expressions include arithmetic, powers, implicit multiplication, and constants pi and e. Function calls use LaTeX commands such as \\sqrt{x}, \\sin(x), and \\max{(a,b)}; absolute values use |x|. Raw calls such as max(x, y) and abs(x) are not accepted.

Implicit 3D surfaces use an implicit item with an equation F(x,y,z)=0. Existing fn items containing a z-dependent equality are detected automatically too. Their sampling volume expands automatically when the zero surface crosses one of its faces, so explicit bounds are normally unnecessary. Six-value 3D bounds can still set the starting x, y, and z intervals:

{
  "type": "3d",
  "renderStyle": "solid",
  "bounds": [-2, 2, -2, 2, -2, 2],
  "items": [
    {
      "type": "implicit",
      "equation": "x^2 + y^2 + z^2 + x + y + z = 0",
      "color": "#f59e0b"
    }
  ]
}

Development

Requires Node.js 20.19 or later for the development and lint toolchain.

npm install
npm run dev

The development build watches for changes. To create a production build in dist/, run:

npm run build

To build the plugin and run the mesh-worker tests, run:

npm run test:worker

License

This project is licensed under the MIT License. See LICENSE.