3D Force-Directed Graph
=======================

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<p align="center">
     <a href="https://vasturiano.github.io/3d-force-graph/example/large-graph/"><img width="80%" src="https://vasturiano.github.io/3d-force-graph/example/preview.png"></a>
</p>

A web component to represent a graph data structure in a 3-dimensional space using a [force-directed](https://en.wikipedia.org/wiki/Force-directed_graph_drawing) iterative layout.
Uses [ThreeJS](https://github.com/mrdoob/three.js/)/WebGL for 3D rendering and either [d3-force-3d](https://github.com/vasturiano/d3-force-3d) or [ngraph](https://github.com/anvaka/ngraph.forcelayout3d) for the underlying physics engine.

See also the [2D canvas version](https://github.com/vasturiano/force-graph), [VR version](https://github.com/vasturiano/3d-force-graph-vr) and [AR version](https://github.com/vasturiano/3d-force-graph-ar).

And check out the [React bindings](https://github.com/vasturiano/react-force-graph).

## Examples

* [Basic](https://vasturiano.github.io/3d-force-graph/example/basic/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/basic/index.html))
* [Asynchronous load](https://vasturiano.github.io/3d-force-graph/example/async-load/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/async-load/index.html))
* [Larger graph (~4k elements)](https://vasturiano.github.io/3d-force-graph/example/large-graph/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/large-graph/index.html))
* [Directional arrows](https://vasturiano.github.io/3d-force-graph/example/directional-links-arrows/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/directional-links-arrows/index.html))
* [Directional moving particles](https://vasturiano.github.io/3d-force-graph/example/directional-links-particles/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/directional-links-particles/index.html))
* [Curved lines and self links](https://vasturiano.github.io/3d-force-graph/example/curved-links/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/curved-links/index.html))
* [Auto-colored nodes/links](https://vasturiano.github.io/3d-force-graph/example/auto-colored/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/auto-colored/index.html))
* [Text as nodes](https://vasturiano.github.io/3d-force-graph/example/text-nodes/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/text-nodes/index.html))
* [Images as nodes](https://vasturiano.github.io/3d-force-graph/example/img-nodes/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/img-nodes/index.html))
* [HTML in nodes](https://vasturiano.github.io/3d-force-graph/example/html-nodes/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/html-nodes/index.html))
* [Custom node geometries](https://vasturiano.github.io/3d-force-graph/example/custom-node-geometry/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/custom-node-geometry/index.html))
* [Gradient Links](https://vasturiano.github.io/3d-force-graph/example/gradient-links/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/gradient-links/index.html))
* [Text in Links](https://vasturiano.github.io/3d-force-graph/example/text-links/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/text-links/index.html))
* [Orbit controls](https://vasturiano.github.io/3d-force-graph/example/controls-orbit/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/controls-orbit/index.html))
* [Fly controls](https://vasturiano.github.io/3d-force-graph/example/controls-fly/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/controls-fly/index.html))
* [Camera automatic orbitting](https://vasturiano.github.io/3d-force-graph/example/camera-auto-orbit/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/camera-auto-orbit/index.html))
* [Click to focus on node](https://vasturiano.github.io/3d-force-graph/example/click-to-focus/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/click-to-focus/index.html))
* [Click to expand/collapse nodes](https://vasturiano.github.io/3d-force-graph/example/expandable-nodes/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/expandable-nodes/index.html))
* [Fix nodes after dragging](https://vasturiano.github.io/3d-force-graph/example/fix-dragged-nodes/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/fix-dragged-nodes/index.html))
* [Fit graph to canvas](https://vasturiano.github.io/3d-force-graph/example/fit-to-canvas/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/fit-to-canvas/index.html))
* [Highlight nodes/links](https://vasturiano.github.io/3d-force-graph/example/highlight/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/highlight/index.html))
* [Multiple Node Selection](https://vasturiano.github.io/3d-force-graph/example/multi-selection/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/multi-selection/index.html))
* [Dynamic data changes](https://vasturiano.github.io/3d-force-graph/example/dynamic/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/dynamic/index.html))
* [Node collision detection](https://vasturiano.github.io/3d-force-graph/example/collision-detection/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/collision-detection/index.html))
* [Manipulate link force distance](https://vasturiano.github.io/3d-force-graph/example/manipulate-link-force/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/manipulate-link-force/index.html))
* [Emit link particles on demand](https://vasturiano.github.io/3d-force-graph/example/emit-particles/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/emit-particles/index.html))
* [Force-directed tree (DAG mode)](https://vasturiano.github.io/3d-force-graph/example/tree/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/tree/index.html))
* [yarn.lock dependency graph (DAG mode)](https://vasturiano.github.io/3d-force-graph/example/dag-yarn/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/dag-yarn/index.html))
* [Add external objects to scene](https://vasturiano.github.io/3d-force-graph/example/scene/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/scene/index.html))
* [Bloom Post-Processing Effect](https://vasturiano.github.io/3d-force-graph/example/bloom-effect/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/bloom-effect/index.html))
* [Pause / Resume animation](https://vasturiano.github.io/3d-force-graph/example/pause-resume/) ([source](https://github.com/vasturiano/3d-force-graph/blob/master/example/pause-resume/index.html))

## Quick start

```js
import ForceGraph3D from '3d-force-graph';
```

or using a *script* tag

```html
<script src="//unpkg.com/3d-force-graph"></script>
```

then

```js
const myGraph = ForceGraph3D();
myGraph(<myDOMElement>)
  .graphData(<myData>);
```

## API reference

### Initialisation
```js
ForceGraph3d({ configOptions })(<domElement>)
```

| Config options | Description | Default |
| --- | --- | :--: |
| <b>controlType</b>: <i>str</i> | Which type of control to use to control the camera. Choice between [trackball](https://threejs.org/examples/misc_controls_trackball.html), [orbit](https://threejs.org/examples/#misc_controls_orbit) or [fly](https://threejs.org/examples/misc_controls_fly.html). | `trackball` |
| <b>rendererConfig</b>: <i>object</i> | Configuration parameters to pass to the [ThreeJS WebGLRenderer](https://threejs.org/docs/#api/en/renderers/WebGLRenderer) constructor. | `{ antialias: true, alpha: true }` |
| <b>extraRenderers</b>: <i>array</i> | If you wish to include custom objects that require a dedicated renderer besides `WebGL`, such as [CSS3DRenderer](https://threejs.org/docs/#examples/en/renderers/CSS3DRenderer), include in this array those extra renderer instances. | `[]` |

### Data input

| Method | Description | Default |
| --- | --- | :--: |
| <b>graphData</b>([<i>data</i>]) | Getter/setter for graph data structure (see below for syntax details). Can also be used to apply [incremental updates](https://bl.ocks.org/vasturiano/2f602ea6c51c664c29ec56cbe2d6a5f6). | `{ nodes: [], links: [] }` |
| <b>jsonUrl</b>([<i>url</i>]) | URL of JSON file to load graph data directly from, as an alternative to specifying <i>graphData</i> directly. | |
| <b>nodeId</b>([<i>str</i>]) | Node object accessor attribute for unique node id (used in link objects source/target). | `id` |
| <b>linkSource</b>([<i>str</i>]) | Link object accessor attribute referring to id of source node. | `source` |
| <b>linkTarget</b>([<i>str</i>]) | Link object accessor attribute referring to id of target node. | `target` |

### Container layout

| Method | Description | Default |
| --- | --- | :--: |
| <b>width</b>([<i>px</i>]) | Getter/setter for the canvas width. | *&lt;window width&gt;* |
| <b>height</b>([<i>px</i>]) | Getter/setter for the canvas height. | *&lt;window height&gt;* |
| <b>backgroundColor</b>([<i>str</i>]) | Getter/setter for the chart background color. | `#000011` |
| <b>showNavInfo</b>([<i>boolean</i>]) | Getter/setter for whether to show the navigation controls footer info. | `true` |

### Node styling

| Method | Description | Default |
| --- | --- | :--: |
| <b>nodeRelSize</b>([<i>num</i>]) | Getter/setter for the ratio of node sphere volume (cubic px) per value unit. | 4 |
| <b>nodeVal</b>([<i>num</i>, <i>str</i> or <i>fn</i>]) | Node object accessor function, attribute or a numeric constant for the node numeric value (affects sphere volume). | `val` |
| <b>nodeLabel</b>([<i>str</i> or <i>fn</i>]) | Node object accessor function or attribute for name (shown in label). Supports plain text or HTML content. Note that this method uses `innerHTML` internally, so make sure to pre-sanitize any user-input content to prevent XSS vulnerabilities. | `name` |
| <b>nodeVisibility</b>([<i>boolean</i>, <i>str</i> or <i>fn</i>]) | Node object accessor function, attribute or a boolean constant for whether to display the node. | `true` |
| <b>nodeColor</b>([<i>str</i> or <i>fn</i>]) | Node object accessor function or attribute for node color (affects sphere color). | `color` |
| <b>nodeAutoColorBy</b>([<i>str</i> or <i>fn</i>]) | Node object accessor function (`fn(node)`) or attribute (e.g. `'type'`) to automatically group colors by. Only affects nodes without a color attribute. | |
| <b>nodeOpacity</b>([<i>num</i>]) | Getter/setter for the nodes sphere opacity, between [0,1]. | 0.75   |
| <b>nodeResolution</b>([<i>num</i>]) | Getter/setter for the geometric resolution of each node, expressed in how many slice segments to divide the circumference. Higher values yield smoother spheres. | 8 |
| <b>nodeThreeObject</b>([<i>Object3d</i>, <i>str</i> or <i>fn</i>]) | Node object accessor function or attribute for generating a custom 3d object to render as graph nodes. Should return an instance of [ThreeJS Object3d](https://threejs.org/docs/index.html#api/core/Object3D). If a <i>falsy</i> value is returned, the default 3d object type will be used instead for that node.  | *default node object is a sphere, sized according to `val` and styled according to `color`.* |
| <b>nodeThreeObjectExtend</b>([<i>bool</i>, <i>str</i> or <i>fn</i>]) | Node object accessor function, attribute or a boolean value for whether to replace the default node when using a custom `nodeThreeObject` (`false`) or to extend it (`true`).  | `false` |

### Link styling

| Method | Description | Default |
| --- | --- | :--: |
| <b>linkLabel</b>([<i>str</i> or <i>fn</i>]) | Link object accessor function or attribute for name (shown in label). Supports plain text or HTML content. Note that this method uses `innerHTML` internally, so make sure to pre-sanitize any user-input content to prevent XSS vulnerabilities. | `name` |
| <b>linkVisibility</b>([<i>boolean</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a boolean constant for whether to display the link line. A value of `false` maintains the link force without rendering it. | `true` |
| <b>linkColor</b>([<i>str</i> or <i>fn</i>]) | Link object accessor function or attribute for line color. | `color` |
| <b>linkAutoColorBy</b>([<i>str</i> or <i>fn</i>]) | Link object accessor function (`fn(link)`) or attribute (e.g. `'type'`) to automatically group colors by. Only affects links without a color attribute. | |
| <b>linkOpacity</b>([<i>num</i>]) | Getter/setter for line opacity of links, between [0,1]. | 0.2 |
| <b>linkWidth</b>([<i>num</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a numeric constant for the link line width. A value of zero will render a [ThreeJS Line](https://threejs.org/docs/#api/objects/Line) whose width is constant (`1px`) regardless of distance. Values are rounded to the nearest decimal for indexing purposes. | 0 |
| <b>linkResolution</b>([<i>num</i>]) | Getter/setter for the geometric resolution of each link, expressed in how many radial segments to divide the cylinder. Higher values yield smoother cylinders. Applicable only to links with positive width. | 6 |
| <b>linkCurvature</b>([<i>num</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a numeric constant for the curvature radius of the link line. Curved lines are represented as 3D bezier curves, and any numeric value is accepted. A value of `0` renders a straight line. `1` indicates a radius equal to half of the line length, causing the curve to approximate a semi-circle. For self-referencing links (`source` equal to `target`) the curve is represented as a loop around the node, with length proportional to the curvature value. Lines are curved clockwise for positive values, and counter-clockwise for negative values. Note that rendering curved lines is purely a visual effect and does not affect the behavior of the underlying forces. | 0 |
| <b>linkCurveRotation</b>([<i>num</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a numeric constant for the rotation along the line axis to apply to the curve. Has no effect on straight lines. At `0` rotation, the curve is oriented in the direction of the intersection with the `XY` plane. The rotation angle (in radians) will rotate the curved line clockwise around the "start-to-end" axis from this reference orientation. | 0 |
| <b>linkMaterial</b>([<i>Material</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function or attribute for specifying a custom material to style the graph links with. Should return an instance of [ThreeJS Material](https://threejs.org/docs/#api/materials/Material). If a <i>falsy</i> value is returned, the default material will be used instead for that link. | *default link material is [MeshLambertMaterial](https://threejs.org/docs/#api/materials/MeshLambertMaterial) styled according to `color` and `opacity`.* |
| <b>linkThreeObject</b>([<i>Object3d</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function or attribute for generating a custom 3d object to render as graph links. Should return an instance of [ThreeJS Object3d](https://threejs.org/docs/index.html#api/core/Object3D). If a <i>falsy</i> value is returned, the default 3d object type will be used instead for that link.  | *default link object is a line or cylinder, sized according to `width` and styled according to `material`.* |
| <b>linkThreeObjectExtend</b>([<i>bool</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a boolean value for whether to replace the default link when using a custom `linkThreeObject` (`false`) or to extend it (`true`).  | `false` |
| <b>linkPositionUpdate</b>([<i>fn(linkObject, { start, end }, link)</i>]) | Getter/setter for the custom function to call for updating the position of links at every render iteration. It receives the respective link `ThreeJS Object3d`, the `start` and `end` coordinates of the link (`{x,y,z}` each), and the link's `data`. If the function returns a truthy value, the regular position update function will not run for that link. | |
| <b>linkDirectionalArrowLength</b>([<i>num</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a numeric constant for the length of the arrow head indicating the link directionality. The arrow is displayed directly over the link line, and points in the direction of `source` > `target`. A value of `0` hides the arrow. | 0 |
| <b>linkDirectionalArrowColor</b>([<i>str</i> or <i>fn</i>]) | Link object accessor function or attribute for the color of the arrow head. | `color` |
| <b>linkDirectionalArrowRelPos</b>([<i>num</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a numeric constant for the longitudinal position of the arrow head along the link line, expressed as a ratio between `0` and `1`, where `0` indicates immediately next to the `source` node, `1` next to the `target` node, and `0.5` right in the middle. | 0.5 |
| <b>linkDirectionalArrowResolution</b>([<i>num</i>]) | Getter/setter for the geometric resolution of the arrow head, expressed in how many slice segments to divide the cone base circumference. Higher values yield smoother arrows. | 8 |
| <b>linkDirectionalParticles</b>([<i>num</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a numeric constant for the number of particles (small spheres) to display over the link line. The particles are distributed equi-spaced along the line, travel in the direction `source` > `target`, and can be used to indicate link directionality. | 0 |
| <b>linkDirectionalParticleSpeed</b>([<i>num</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a numeric constant for the directional particles speed, expressed as the ratio of the link length to travel per frame. Values above `0.5` are discouraged. | 0.01 |
| <b>linkDirectionalParticleWidth</b>([<i>num</i>, <i>str</i> or <i>fn</i>]) | Link object accessor function, attribute or a numeric constant for the directional particles width. Values are rounded to the nearest decimal for indexing purposes. | 0.5 |
| <b>linkDirectionalParticleColor</b>([<i>str</i> or <i>fn</i>]) | Link object accessor function or attribute for the directional particles color. | `color` |
| <b>linkDirectionalParticleResolution</b>([<i>num</i>]) | Getter/setter for the geometric resolution of each directional particle, expressed in how many slice segments to divide the circumference. Higher values yield smoother particles. | 4 |
| <b>emitParticle</b>(<i>link</i>) | An alternative mechanism for generating particles, this method emits a non-cyclical single particle within a specific link. The emitted particle shares the styling (speed, width, color) of the regular particle props. A valid `link` object that is included in `graphData` should be passed as a single parameter. ||

### Render control

| Method | Description | Default |
| --- | --- | :--: |
| <b>pauseAnimation</b>() | Pauses the rendering cycle of the component, effectively freezing the current view and cancelling all user interaction. This method can be used to save performance in circumstances when a static image is sufficient. | |
| <b>resumeAnimation</b>() | Resumes the rendering cycle of the component, and re-enables the user interaction. This method can be used together with `pauseAnimation` for performance optimization purposes. | |
| <b>cameraPosition</b>([<i>{x,y,z}</i>], [<i>lookAt</i>], [<i>ms</i>]) | Getter/setter for the camera position, in terms of `x`, `y`, `z` coordinates. Each of the coordinates is optional, allowing for motion in just some dimensions. The optional second argument can be used to define the direction that the camera should aim at, in terms of an `{x,y,z}` point in the 3D space. The 3rd optional argument defines the duration of the transition (in ms) to animate the camera motion. A value of 0 (default) moves the camera immediately to the final position. | By default the camera will face the center of the graph at a `z` distance proportional to the amount of nodes in the system. |
| <b>zoomToFit</b>([<i>ms</i>], [<i>px</i>], [<i>nodeFilterFn</i>]) | Automatically moves the camera so that all of the nodes become visible within its field of view, aiming at the graph center (0,0,0). If no nodes are found no action is taken. It accepts three optional arguments: the first defines the duration of the transition (in ms) to animate the camera motion (default: 0ms). The second argument is the amount of padding (in px) between the edge of the canvas and the outermost node location (default: 10px). The third argument specifies a custom node filter: `node => <boolean>`, which should return a truthy value if the node is to be included. This can be useful for focusing on a portion of the graph. | `(0, 10, node => true)` |
| <b>postProcessingComposer</b>() | Access the [post-processing composer](https://threejs.org/docs/#examples/en/postprocessing/EffectComposer). Use this to add post-processing [rendering effects](https://github.com/mrdoob/three.js/tree/dev/examples/jsm/postprocessing) to the scene. By default the composer has a single pass ([RenderPass](https://github.com/mrdoob/three.js/blob/dev/examples/jsm/postprocessing/RenderPass.js)) that directly renders the scene without any effects. || 
| <b>lights</b>([<i>array</i>]) | Getter/setter for the list of lights to use in the scene. Each item should be an instance of [Light](https://threejs.org/docs/#api/en/lights/Light). | [AmbientLight](https://threejs.org/docs/?q=ambient#api/en/lights/AmbientLight) + [DirectionalLight](https://threejs.org/docs/#api/en/lights/DirectionalLight) (from above) |
| <b>scene</b>() | Access the internal ThreeJS [Scene](https://threejs.org/docs/#api/scenes/Scene). Can be used to extend the current scene with additional objects not related to 3d-force-graph. | |
| <b>camera</b>() | Access the internal ThreeJS [Camera](https://threejs.org/docs/#api/cameras/PerspectiveCamera). | |
| <b>renderer</b>() | Access the internal ThreeJS [WebGL renderer](https://threejs.org/docs/#api/renderers/WebGLRenderer). ||
| <b>controls</b>() | Access the internal ThreeJS controls object. ||
| <b>refresh</b>() | Redraws all the nodes/links. |

### Force engine configuration

| Method | Description | Default |
| --- | --- | :--: |
| <b>forceEngine</b>([<i>str</i>]) | Getter/setter for which force-simulation engine to use ([*d3*](https://github.com/vasturiano/d3-force-3d) or [*ngraph*](https://github.com/anvaka/ngraph.forcelayout)). | `d3` |
| <b>numDimensions</b>([<i>int</i>]) | Getter/setter for number of dimensions to run the force simulation on (1, 2 or 3). | 3 |
| <b>dagMode</b>([<i>str</i>]) | Apply layout constraints based on the graph directionality. Only works correctly for [DAG](https://en.wikipedia.org/wiki/Directed_acyclic_graph) graph structures (without cycles). Choice between `td` (top-down), `bu` (bottom-up), `lr` (left-to-right), `rl` (right-to-left), `zout` (near-to-far), `zin` (far-to-near), `radialout` (outwards-radially) or `radialin` (inwards-radially). | |
| <b>dagLevelDistance</b>([<i>num</i>]) | If `dagMode` is engaged, this specifies the distance between the different graph depths. | *auto-derived from the number of nodes* |
| <b>dagNodeFilter</b>([<i>fn</i>]) | Node accessor function to specify nodes to ignore during the DAG layout processing. This accessor method receives a node object and should return a `boolean` value indicating whether the node is to be included. Excluded nodes will be left unconstrained and free to move in any direction. | `node => true` |
| <b>onDagError</b>([<i>fn</i>]) | Callback to invoke if a cycle is encountered while processing the data structure for a DAG layout. The loop segment of the graph is included for information, as an array of node ids. By default an exception will be thrown whenever a loop is encountered. You can override this method to handle this case externally and allow the graph to continue the DAG processing. Strict graph directionality is not guaranteed if a loop is encountered and the result is a best effort to establish a hierarchy. | *throws exception* |
| <b>d3AlphaMin</b>([<i>num</i>]) | Getter/setter for the [simulation alpha min](https://github.com/vasturiano/d3-force-3d#simulation_alphaMin) parameter, only applicable if using the d3 simulation engine. | `0` |
| <b>d3AlphaDecay</b>([<i>num</i>]) | Getter/setter for the [simulation intensity decay](https://github.com/vasturiano/d3-force-3d#simulation_alphaDecay) parameter, only applicable if using the d3 simulation engine. | `0.0228` |
| <b>d3VelocityDecay</b>([<i>num</i>]) | Getter/setter for the nodes' [velocity decay](https://github.com/vasturiano/d3-force-3d#simulation_velocityDecay) that simulates the medium resistance, only applicable if using the d3 simulation engine. | `0.4` |
| <b>d3Force</b>(<i>str</i>, [<i>fn</i>]) | Getter/setter for the internal forces that control the d3 simulation engine. Follows the same interface as `d3-force-3d`'s [simulation.force](https://github.com/vasturiano/d3-force-3d#simulation_force). Three forces are included by default: `'link'` (based on [forceLink](https://github.com/vasturiano/d3-force-3d#forceLink)), `'charge'` (based on [forceManyBody](https://github.com/vasturiano/d3-force-3d#forceManyBody)) and `'center'` (based on [forceCenter](https://github.com/vasturiano/d3-force-3d#forceCenter)). Each of these forces can be reconfigured, or new forces can be added to the system. This method is only applicable if using the d3 simulation engine. | |
| <b>d3ReheatSimulation</b>() | Reheats the force simulation engine, by setting the `alpha` value to `1`. Only applicable if using the d3 simulation engine. | |
| <b>ngraphPhysics</b>([<i>object</i>]) | Specify custom physics configuration for ngraph, according to its [configuration object](https://github.com/anvaka/ngraph.forcelayout#configuring-physics) syntax. This method is only applicable if using the ngraph simulation engine. | *ngraph default* |
| <b>warmupTicks</b>([<i>int</i>]) | Getter/setter for number of layout engine cycles to dry-run at ignition before starting to render. | 0 |
| <b>cooldownTicks</b>([<i>int</i>]) | Getter/setter for how many build-in frames to render before stopping and freezing the layout engine. | Infinity |
| <b>cooldownTime</b>([<i>num</i>]) | Getter/setter for how long (ms) to render for before stopping and freezing the layout engine. | 15000 |
| <b>onEngineTick</b>(<i>fn</i>) | Callback function invoked at every tick of the simulation engine. | - |
| <b>onEngineStop</b>(<i>fn</i>) | Callback function invoked when the simulation engine stops and the layout is frozen. | - |

### Interaction

| Method | Description | Default |
| --- | --- | :--: |
| <b>onNodeClick</b>(<i>fn</i>) | Callback function for node (left-button) clicks. The node object and the event object are included as arguments `onNodeClick(node, event)`. | - |
| <b>onNodeRightClick</b>(<i>fn</i>) | Callback function for node right-clicks. The node object and the event object are included as arguments `onNodeRightClick(node, event)`. | - |
| <b>onNodeHover</b>(<i>fn</i>) | Callback function for node mouse over events. The node object (or `null` if there's no node under the mouse line of sight) is included as the first argument, and the previous node object (or null) as second argument: `onNodeHover(node, prevNode)`. | - |
| <b>onNodeDrag</b>(<i>fn</i>) | Callback function for node drag interactions. This function is invoked repeatedly while dragging a node, every time its position is updated. The node object is included as the first argument, and the change in coordinates since the last iteration of this function are included as the second argument in format {x,y,z}: `onNodeDrag(node, translate)`. | - |
| <b>onNodeDragEnd</b>(<i>fn</i>) | Callback function for the end of node drag interactions. This function is invoked when the node is released. The node object is included as the first argument, and the entire change in coordinates from initial location are included as the second argument in format {x,y,z}: `onNodeDragEnd(node, translate)`. | - |
| <b>onLinkClick</b>(<i>fn</i>) | Callback function for link (left-button) clicks. The link object and the event object are included as arguments `onLinkClick(link, event)`. | - |
| <b>onLinkRightClick</b>(<i>fn</i>) | Callback function for link right-clicks. The link object and the event object are included as arguments `onLinkRightClick(link, event)`. | - |
| <b>onLinkHover</b>(<i>fn</i>) | Callback function for link mouse over events. The link object (or `null` if there's no link under the mouse line of sight) is included as the first argument, and the previous link object (or null) as second argument: `onLinkHover(link, prevLink)`. | - |
| <b>onBackgroundClick</b>(<i>fn</i>) | Callback function for click events on the empty space between the nodes and links. The event object is included as single argument `onBackgroundClick(event)`. | - |
| <b>onBackgroundRightClick</b>(<i>fn</i>) | Callback function for right-click events on the empty space between the nodes and links. The event object is included as single argument `onBackgroundRightClick(event)`. | - |
| <b>linkHoverPrecision</b>([<i>int</i>]) | Whether to display the link label when gazing the link closely (low value) or from far away (high value). | 1 |
| <b>enablePointerInteraction</b>([<i>boolean</i>]) | Getter/setter for whether to enable the mouse tracking events. This activates an internal tracker of the canvas mouse position and enables the functionality of object hover/click and tooltip labels, at the cost of performance. If you're looking for maximum gain in your graph performance it's recommended to switch off this property. | `true` |
| <b>enableNodeDrag</b>([<i>boolean</i>]) | Getter/setter for whether to enable the user interaction to drag nodes by click-dragging. Only supported on the `d3` force engine. If enabled, every time a node is dragged the simulation is re-heated so the other nodes react to the changes. Only applicable if enablePointerInteraction is `true` and using the `d3` force engine. | `true` |
| <b>enableNavigationControls</b>([<i>boolean</i>]) | Getter/setter for whether to enable the trackball navigation controls used to move the camera using mouse interactions (rotate/zoom/pan). | `true` |

###  Utility

| Method | Description |
| --- | --- |
| <b>getGraphBbox</b>([<i>nodeFilterFn</i>]) | Returns the current bounding box of the nodes in the graph, formatted as `{ x: [<num>, <num>], y: [<num>, <num>], z: [<num>, <num>] }`. If no nodes are found, returns `null`. Accepts an optional argument to define a custom node filter: `node => <boolean>`, which should return a truthy value if the node is to be included. This can be useful to calculate the bounding box of a portion of the graph. ||
| <b>graph2ScreenCoords</b>(<i>x</i>, <i>y</i>, <i>z</i>) | Utility method to translate node coordinates to the viewport domain. Given a set of `x`,`y`,`z` graph coordinates, returns the current equivalent `{x, y}` in viewport coordinates. |
| <b>screen2GraphCoords</b>(<i>x</i>, <i>y</i>, <i>distance</i>) | Utility method to translate viewport distance coordinates to the graph domain. Given a pair of `x`,`y` screen coordinates and distance from the camera, returns the current equivalent `{x, y, z}` in the domain of graph node coordinates. |

### Input JSON syntax
```json
{
    "nodes": [
        {
          "id": "id1",
          "name": "name1",
          "val": 1
        },
        {
          "id": "id2",
          "name": "name2",
          "val": 10
        },
        ...
    ],
    "links": [
        {
            "source": "id1",
            "target": "id2"
        },
        ...
    ]
}
```

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[npm-img]: https://img.shields.io/npm/v/3d-force-graph
[npm-url]: https://npmjs.org/package/3d-force-graph
[build-size-img]: https://img.shields.io/bundlephobia/minzip/3d-force-graph
[build-size-url]: https://bundlephobia.com/result?p=3d-force-graph
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[npm-downloads-url]: https://www.npmtrends.com/3d-force-graph
