aframe-forcegraph-component

A 3D Force-Directed Graph component for A-Frame.

An A-Frame entity component to represent a graph data structure in a VR environment using a force-directed iterative layout. Uses three-forcegraph as the underlying ThreeJS component to manage the graph object.

See also the VR and AR standalone component versions.

API

Property	Description	Default Value
json-url	URL of JSON file to load graph data directly from. Will override content of the nodes and links component properties so either use one or the other. JSON should contain an object with two list properties: nodes and links.
nodes	List of node objects. Example: [{"id": 1, "name": "first"}, {"id": 2, "name": "second"}]	[]
links	List of link objects. Example: [{"source": 1, "target": 2}]	[]
num-dimensions	Number of dimensions to run the force simulation on (1, 2 or 3).	3
dag-mode	Apply layout constraints based on the graph directionality. Only works for DAG 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).
dag-level-distance	If dag-mode is engaged, this specifies the distance between the different graph depths.	auto-derived from the number of nodes
dag-node-filter	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.	node => true
on-dag-error	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.	throws exception
node-rel-size	Node sphere volume per value unit.	4
node-id	Node object accessor attribute for unique node id (used in link objects source/target).	id
node-val	Node object accessor function, attribute or a numeric constant for the node numeric value (affects sphere volume).	val
node-resolution	Geometric resolution of each node, expressed in how many slice segments to divide the circumference. Higher values yield smoother spheres.	8
node-visibility	Node object accessor function, attribute or a boolean constant for whether to display the node.	true
node-color	Node object accessor function or attribute for node color (affects sphere color).	color
node-auto-color-by	Node object accessor function (fn(node)) or attribute (e.g. 'type') to automatically group colors by. Only affects nodes without a color attribute.
node-opacity	Nodes sphere opacity, between [0,1].	0.75
node-three-object	Node object accessor function or attribute for generating a custom 3d object to render as graph nodes. Should return an instance of ThreeJS Object3d. If a falsy 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.
node-three-object-extend	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-source	Link object accessor attribute referring to id of source node.	source
link-target	Link object accessor attribute referring to id of target node.	target
link-visibility	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
link-color	Link object accessor function or attribute for line color.	color
link-auto-color-by	Link object accessor function (fn(link)) or attribute (e.g. 'type') to automatically group colors by. Only affects links without a color attribute.
link-opacity	Line opacity of links, between [0,1].	0.2
link-width	Link object accessor function, attribute or a numeric constant for the link line width. A value of zero will render a ThreeJS Line whose width is constant (1px) regardless of distance. Values are rounded to the nearest decimal for indexing purposes.	0
link-resolution	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
link-curvature	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
link-curve-rotation	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
link-material	Link object accessor function or attribute for specifying a custom material to style the graph links with. Should return an instance of ThreeJS Material. If a falsy value is returned, the default material will be used instead for that link.	default link material is MeshLambertMaterial styled according to color and opacity.
link-three-object	Link object accessor function or attribute for generating a custom 3d object to render as graph links. Should return an instance of ThreeJS Object3d. If a falsy 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.
link-three-object-extend	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
link-position-update	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.
link-directional-arrow-length	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
link-directional-arrow-color	Link object accessor function or attribute for the color of the arrow head.	color
link-directional-arrow-rel-pos	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
link-directional-arrow-resolution	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
link-directional-particles	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
link-directional-particle-speed	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
link-directional-particle-width	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
link-directional-particle-color	Link object accessor function or attribute for the directional particles color.	color
link-directional-particle-resolution	Geometric resolution of each directional particle, expressed in how many slice segments to divide the circumference. Higher values yield smoother particles.	4
on-node-hover	Callback function for node hover events, using any raycaster based controller. The node object (or null if there's no node directly on the ray) is included as the first argument, and the previous node object (or null) as second argument.
on-link-hover	Callback function for link hover events, using any raycaster based controller. The link object (or null if there's no link directly on the ray) is included as the first argument, and the previous link object (or null) as second argument.
on-node-click	Callback function for node click events. The node object is included as sole argument.
on-link-click	Callback function for link click events. The link object is included as sole argument.
force-engine	Which force-simulation engine to use (d3 or ngraph).	d3
d3-alpha-min	Simulation alpha min parameter, only applicable if using the d3 simulation engine.	0
d3-alpha-decay	Simulation intensity decay parameter, only applicable if using the d3 simulation engine.	0.0228
d3-velocity-decay	Nodes' velocity decay that simulates the medium resistance, only applicable if using the d3 simulation engine.	0.4
ngraph-physics	Specify custom physics configuration for ngraph, according to its configuration object syntax. Only applicable if using the ngraph simulation engine.	ngraph default
warmup-ticks	How many times to tick the force simulation engine at ignition before starting to render.	0
cooldown-ticks	How many times to tick the force simulation engine after rendering begins before stopping and freezing the engine.	Infinity
cooldown-time	How long (ms) to tick the force simulation engine for after rendering begins before stopping and freezing the engine.	15000
on-engine-tick	Callback function invoked at every tick of the simulation engine.
on-engine-stop	Callback function invoked when the simulation engine stops and the layout is frozen.

There are also internal methods that can be invoked via the components object:

Method	Arguments	Description
d3Force	id: string, [force: function]	Getter/setter for the internal forces that control the d3 simulation engine. Follows the same interface as d3-force-3d's simulation.force. Three forces are included by default: 'link' (based on forceLink), 'charge' (based on forceManyBody) and 'center' (based on 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.
d3ReheatSimulation	-	Reheats the force simulation engine, by setting the alpha value to 1. Only applicable if using the d3 simulation engine.
emitParticle	link: object	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 links should be passed as a single parameter.
getGraphBbox	[nodeFilter: function]	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.
refresh	-	Redraws all the nodes/links.

Installation

Browser

Install and use by directly including the browser files:

<head>
  <title>My A-Frame Scene</title>
  <script src="https://unpkg.com/aframe"></script>
  <script src="https://unpkg.com/aframe-forcegraph-component"></script>
</head>

<body>
  <a-scene>
    <a-entity forcegraph="json-url: myGraphData.json"></a-entity>
  </a-scene>
</body>

npm

Install via npm:

npm install aframe-forcegraph-component

Then require and use.

require('aframe');
require('aframe-forcegraph-component');

Giving Back

If this project has helped you and you'd like to contribute back, you can always buy me a ☕!