     collide: (node) =>
         node = node._d3
         conf = alchemy.conf
-        r = 2 * (node.r + node['stroke-width']) + conf.nodeOverlap
+        r = 2 * (node.radius + node['stroke-width']) + conf.nodeOverlap
         nx1 = node.x - r
         nx2 = node.x + r
         ny1 = node.y - r

                    node.y -= y *= l
                    quad.point.x += x
                    quad.point.y += y
            x1 > nx2 or
            x2 < nx1 or
            y1 > ny2 or

        nodes = alchemy._nodes
        @k = Math.sqrt Math.log(_.size(alchemy._nodes)) / (conf.graphWidth() * conf.graphHeight())
        @_clustering = new alchemy.clustering

        # Set up quad tree
        if conf.collisionDetection
            @d3NodeInternals = _.values alchemy._nodes
            @q = d3.geom.quadtree @d3NodeInternals
        
        if conf.cluster
            @_charge = () -> @_clustering.layout.charge
            @_linkStrength = (edge) -> @_clustering.layout.linkStrength(edge)
