Controls how, and if, edges are represented. If true, edges are drawn as splines routed around nodes; if false, edges are drawn as line segments. If set to none or "", no edges are drawn at all.

(1 March 2007) The values line and spline can be used as synonyms for false and true, respectively. In addition, the value polyline specifies that edges should be drawn as polylines.

(28 Sep 2010) The value ortho specifies edges should be routed as polylines of axis-aligned segments. Currently, the routing does not handle ports or, in dot, edge labels.

(25 Sep 2012) The value curved specifies edges should be drawn as curved arcs.

splines=none	splines=line
splines=""	splines=false
splines=polyline	splines=curved
splines=ortho	splines=spline
	splines=true

By default, the attribute is unset. How this is interpreted depends on the layout. For dot, the default is to draw edges as splines. For all other layouts, the default is to draw edges as line segments. Note that for these latter layouts, if splines="true", this requires non-overlapping nodes (cf. overlap). If fdp is used for layout and splines="compound", then the edges are drawn to avoid clusters as well as nodes.