example/multi-selection/index.html

<head>
  <style> body { margin: 0; } </style>

  <script src="//unpkg.com/3d-force-graph"></script>
<!--  <script src="../../dist/3d-force-graph.js"></script>-->
</head>

<body>
  <div id="3d-graph"></div>

  <script>
    // Random tree
    const N = 40;
    const gData = {
      nodes: [...Array(N).keys()].map(i => ({ id: i })),
      links: [...Array(N).keys()]
        .filter(id => id)
        .map(id => ({
          source: id,
          target: Math.round(Math.random() * (id-1))
        }))
    };

    let selectedNodes = new Set();

    const Graph = new ForceGraph3D(document.getElementById('3d-graph'))
        .graphData(gData)
        .nodeRelSize(9)
        .nodeColor(node => selectedNodes.has(node) ? 'yellow' : 'grey')
        .onNodeClick((node, event) => {
          if (event.ctrlKey || event.shiftKey || event.altKey) { // multi-selection
            selectedNodes.has(node) ? selectedNodes.delete(node) : selectedNodes.add(node);
          } else { // single-selection
            const untoggle = selectedNodes.has(node) && selectedNodes.size === 1;
            selectedNodes.clear();
            !untoggle && selectedNodes.add(node);
          }

          Graph.nodeColor(Graph.nodeColor()); // update color of selected nodes
        })
        .onNodeDrag((node, translate) => {
          if (selectedNodes.has(node)) { // moving a selected node
            [...selectedNodes]
              .filter(selNode => selNode !== node) // don't touch node being dragged
              .forEach(node => ['x', 'y', 'z'].forEach(coord => node[`f${coord}`] = node[coord] + translate[coord])); // translate other nodes by same amount
          }
        })
        .onNodeDragEnd(node => {
          if (selectedNodes.has(node)) { // finished moving a selected node
            [...selectedNodes]
              .filter(selNode => selNode !== node) // don't touch node being dragged
              .forEach(node => ['x', 'y', 'z'].forEach(coord => node[`f${coord}`] = undefined)); // unfix controlled nodes
          }
        });
  </script>
</body>