diff --git a/src/constraint/Constraint.js b/src/constraint/Constraint.js
index 29930b8..d3854ff 100644
--- a/src/constraint/Constraint.js
+++ b/src/constraint/Constraint.js
@@ -42,9 +42,13 @@ var Constraint = {};
         constraint.length = constraint.length || length || _minLength;
 
         // render
-        constraint.render = constraint.render || {};
-        constraint.render.lineWidth = constraint.render.lineWidth || 2;
-        constraint.render.strokeStyle = constraint.render.strokeStyle || '#666';
+        var render = {
+            visible: true,
+            lineWidth: 2,
+            strokeStyle: '#666'
+        };
+        
+        constraint.render = Common.extend(render, constraint.render);
 
         // option defaults
         constraint.stiffness = constraint.stiffness || 1;
diff --git a/src/render/Render.js b/src/render/Render.js
index 59be0b2..f30d8bc 100644
--- a/src/render/Render.js
+++ b/src/render/Render.js
@@ -188,7 +188,7 @@ var Render = {};
             bodyB = constraint.bodyB,
             c = context;
 
-        if (!constraint.pointA || !constraint.pointB)
+        if (!constraint.render.visible || !constraint.pointA || !constraint.pointB)
             return;
 
         if (bodyA) {