1.you neet to set cx and cy of circle to position the circle 2.you need to set x1 y1, x2 y2 of line to position line
3.if you need active you need to listen to tick event of force layout
var w = 300;
var h = 300;
var dataset = {
nodes: [{
name: 'Aden'
}, {
name: 'Bob'
}, {
name: 'Sue'
}],
edges: [{
source: 0,
target: 1
}, {
source: 1,
target: 2
}]
};
var svg = d3.select("body")
.append("svg")
.attr("height", h)
.attr("width", w);
var force = d3.layout.force()
.nodes(dataset.nodes)
.links(dataset.edges)
.size([w, h])
.on("tick", tick) // listener tick to listen position change
.linkDistance([50])
.start();
var nodes = svg.selectAll("circle")
.data(dataset.nodes)
.enter()
.append("circle")
.attr("r", 10)
// set cx cy of circle to position the circle
.attr("cx", function (d) {return d.x; })
.attr("cy", function (d) { return d.y; })
.style("fill", "red")
.call(force.drag);
var edges = svg.selectAll("line")
.data(dataset.edges)
.enter()
.append("line")
// set x1, y1, x2, y2 to position the line
.attr("x1", function (d) {
return d.source.x;
})
.attr("y1", function (d) {
return d.source.y;
})
.attr("x2", function (d) {
return d.target.x;
})
.attr("y2", function (d){
return d.target.y;
})
.style("stroke", "#ccc")
.style("stroke-width", 1);
// make it actively
function tick(e) {
edges.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
nodes.attr("cx", function(d) { return d.x; })
.attr("cy", function(d) { return d.y; });
}
demo update: http://jsfiddle.net/MnX23/3/