diff --git a/lib/torque/renderer/iso.js b/lib/torque/renderer/iso.js
index d4aaa70..4786893 100644
--- a/lib/torque/renderer/iso.js
+++ b/lib/torque/renderer/iso.js
@@ -265,6 +265,16 @@ torque.extend(IsoRenderer.prototype, torque.Event, {
 		return gctx.getImageData(0, 0, 1, 256).data;
 	},
 
+	cardinalSpline: function(line){
+		var plainArray = [];
+		for (var p = 0; p < line.length; p++){
+			var interpolation = line[p].coord.interpolation || {x: 0.5, y: 0.5};
+			plainArray.push(20 + 20*line[p].coord.x + 20 * interpolation.x);
+			plainArray.push(20 + 20*line[p].coord.y + 20 * interpolation.y);
+		}
+		return cSpline(plainArray, 0.5, 25, true);
+	}
+
 	/*
 		CARDINAL SPLINE
 		by Steffen Bär