diff --git a/web/app/sketcher/canvas.js b/web/app/sketcher/canvas.js
index cf381119..82e3b20e 100644
--- a/web/app/sketcher/canvas.js
+++ b/web/app/sketcher/canvas.js
@@ -156,6 +156,11 @@ TCAD.TWO.Viewer.prototype.remove = function(obj) {
   }
 };
 
+TCAD.TWO.Viewer.prototype.add = function(obj, layer) {
+  layer.objects.push(obj);
+  obj.layer = layer;
+};
+
 TCAD.TWO.Viewer.prototype.search = function(x, y, buffer, deep, onlyPoints, filter) {
 
   buffer *= 0.5;
diff --git a/web/app/sketcher/io.js b/web/app/sketcher/io.js
index 6807fff3..39bc9071 100644
--- a/web/app/sketcher/io.js
+++ b/web/app/sketcher/io.js
@@ -7,7 +7,8 @@ TCAD.io.Types = {
   CIRCLE    : 'TCAD.TWO.Circle',
   DIM       : 'TCAD.TWO.Dimension',
   HDIM      : 'TCAD.TWO.HDimension',
-  VDIM      : 'TCAD.TWO.VDimension'
+  VDIM      : 'TCAD.TWO.VDimension',
+  DDIM      : 'TCAD.TWO.DiameterDimension'
 };
 
 /** @constructor */
@@ -100,6 +101,8 @@ TCAD.IO.prototype._loadSketch = function(sketch) {
         } else if (_class === T.DIM) {
           skobj = new TCAD.TWO.Dimension(obj['a'], obj['b']);
           skobj.flip = obj['flip'];
+        } else if (_class === T.DDIM) {
+          skobj = new TCAD.TWO.DiameterDimension(obj['obj']);
         }
         if (skobj != null) {
           if (aux) skobj.accept(function(o){o.aux = true; return true;});
@@ -116,10 +119,12 @@ TCAD.IO.prototype._loadSketch = function(sketch) {
 
   for (i = 0; i < this.viewer.dimLayer.objects.length; ++i) {
     obj = this.viewer.dimLayer.objects[i];
-    //if (obj._class === 'TCAD.TWO.Dimension' || obj._class === 'TCAD.TWO.HDimension' || obj._class === 'TCAD.TWO.VDimension') {
-    obj.a = index[obj.a];
-    obj.b = index[obj.b];
-    //}
+    if (obj._class === T.DIM || obj._class === T.HDIM || obj._class === T.VDIM) {
+      obj.a = index[obj.a];
+      obj.b = index[obj.b];
+    } else if (obj._class === T.DDIM) {
+      obj.obj = index[obj.obj];
+    }
   }
 
   this.setupBoundary(sketch['boundary']);
@@ -187,7 +192,9 @@ TCAD.IO.prototype._serializeSketch = function() {
           to['a'] = obj.a.id;
           to['b'] = obj.b.id;
           to['flip'] = obj.flip;
-        }
+        } else if (obj._class === T.DDIM) {
+          to['obj'] = obj.obj.id;
+        } 
       }
     }
   }
diff --git a/web/app/sketcher/main2d.js b/web/app/sketcher/main2d.js
index d9a68e68..da113840 100644
--- a/web/app/sketcher/main2d.js
+++ b/web/app/sketcher/main2d.js
@@ -114,10 +114,15 @@ TCAD.App2D = function() {
   this.registerAction('addHDim', "Add Horizontal Dimension", function () {
     app.viewer.toolManager.takeControl(new TCAD.TWO.AddDimTool(app.viewer, app.viewer.dimLayer, function(a,b) {return new TCAD.TWO.HDimension(a,b)} ));
   });
+  
   this.registerAction('addVDim', "Add Vertical Dimension", function () {
     app.viewer.toolManager.takeControl(new TCAD.TWO.AddDimTool(app.viewer, app.viewer.dimLayer, function(a,b) {return new TCAD.TWO.VDimension(a,b)} ));
   });
 
+  this.registerAction('addCircleDim', "Add Circle Dimension", function () {
+    app.viewer.toolManager.takeControl(new TCAD.TWO.AddCircleDimTool(app.viewer, app.viewer.dimLayer));
+  });
+
   this.registerAction('save', "Save", function () {
       var sketchData = app.viewer.io.serializeSketch();
       var sketchId = app.getSketchId();
diff --git a/web/app/sketcher/shapes/dim.js b/web/app/sketcher/shapes/dim.js
index c2b53143..42f0719a 100644
--- a/web/app/sketcher/shapes/dim.js
+++ b/web/app/sketcher/shapes/dim.js
@@ -21,10 +21,14 @@ TCAD.TWO.LinearDimension.prototype.translateImpl = function(dx, dy) {
 TCAD.TWO.LinearDimension.prototype.getA = function() { return this.a };
 TCAD.TWO.LinearDimension.prototype.getB = function() { return this.b };
 
+TCAD.TWO.LinearDimension.getTextOff = function(scale) {
+  return 3 * scale;
+};
+
 TCAD.TWO.LinearDimension.prototype.drawImpl = function(ctx, scale, viewer) {
 
   var off = 30 * viewer.dimScale;
-  var textOff = 3 * viewer.dimScale;
+  var textOff = TCAD.TWO.LinearDimension.getTextOff(viewer.dimScale);
 
   var a, b, startA, startB;
   if (this.flip) {
@@ -101,7 +105,7 @@ TCAD.TWO.LinearDimension.prototype.drawImpl = function(ctx, scale, viewer) {
     var ty = (_ay + _vyn * textOff) - (  _vxn) * h;
     ctx.save();
     ctx.translate(tx, ty);
-    ctx.rotate(	- Math.atan2(_vxn, _vyn));		
+    ctx.rotate(	- Math.atan2(_vxn, _vyn));
     ctx.scale(1, -1);
     ctx.fillText(txt, 0, 0);
     ctx.restore();
@@ -145,6 +149,93 @@ TCAD.TWO.VDimension.prototype._class = 'TCAD.TWO.VDimension';
 TCAD.TWO.VDimension.prototype.getA = function() { return this.a };
 TCAD.TWO.VDimension.prototype.getB = function() { return {x : this.a.x, y : this.b.y} };
 
+
+/** @constructor */
+TCAD.TWO.DiameterDimension = function(obj) {
+  TCAD.TWO.SketchObject.call(this);
+  this.obj = obj;
+  this.angle = Math.PI / 4;
+};
+
+TCAD.TWO.DiameterDimension.prototype._class = 'TCAD.TWO.DiameterDimension';
+
+TCAD.TWO.utils.extend(TCAD.TWO.DiameterDimension, TCAD.TWO.SketchObject);
+
+TCAD.TWO.DiameterDimension.prototype.collectParams = function(params) {
+};
+
+TCAD.TWO.DiameterDimension.prototype.getReferencePoint = function() {
+  
+};
+
+TCAD.TWO.DiameterDimension.prototype.translateImpl = function(dx, dy) {
+};
+
+TCAD.TWO.DiameterDimension.prototype.drawImpl = function(ctx, scale, viewer) {
+  if (this.obj == null) return;
+  var c = new TCAD.Vector().setV(this.obj.c);
+  var r = this.obj.r.value;
+  var angled = new TCAD.Vector(r * Math.cos(this.angle), r * Math.sin(this.angle), 0);
+  var a = c.minus(angled);
+  var b = c.plus(angled);
+  var textOff = TCAD.TWO.LinearDimension.getTextOff(viewer.dimScale);
+
+  var d = TCAD.math.distanceAB(a, b);
+
+  ctx.beginPath();
+  ctx.moveTo(a.x, a.y);
+  ctx.lineTo(b.x, b.y);
+  ctx.closePath();
+  ctx.stroke();
+
+  var fontSize = 12 * viewer.dimScale;
+  ctx.font = (fontSize) + "px Arial";
+  var txt = String.fromCharCode(216) + ' ' + d.toFixed(2);
+  var textWidth = ctx.measureText(txt).width;
+  var h = d / 2 - textWidth / 2; 
+  
+  var _vx = - (b.y - a.y);
+  var _vy = b.x - a.x;
+
+  //normalize
+  var _vxn = _vx / d;
+  var _vyn = _vy / d;
+
+  function drawText(tx, ty) {
+    ctx.save();
+    ctx.translate(tx, ty);
+    ctx.rotate(-Math.atan2(_vxn, _vyn));
+    ctx.scale(1, -1);
+    ctx.fillText(txt, 0, 0);
+    ctx.restore();
+  }
+
+  if (h - fontSize * .3 > 0) { // take into account font size to not have circle overlap symbols
+    var tx = (a.x + _vxn * textOff) - (-_vyn) * h;
+    var ty = (a.y + _vyn * textOff) - (  _vxn) * h;
+    drawText(tx, ty);
+  } else {
+    var off = 2 * viewer.dimScale;
+    angled._normalize();
+    var extraLine = angled.multiply(textWidth + off * 2);
+    ctx.beginPath();
+    ctx.moveTo(b.x, b.y);
+    ctx.lineTo(b.x + extraLine.x, b.y + extraLine.y);
+    ctx.closePath();
+    ctx.stroke();
+    angled._multiply(off);
+    
+    var tx = (b.x + _vxn * textOff) + angled.x;
+    var ty = (b.y + _vyn * textOff) + angled.y;
+    drawText(tx, ty);
+  }
+};
+
+TCAD.TWO.DiameterDimension.prototype.normalDistance = function(aim) {
+  return -1;
+};
+
+
 /** @constructor */
 TCAD.TWO.AddDimTool = function(viewer, layer, dimCreation) {
   this.viewer = viewer;
@@ -202,3 +293,47 @@ TCAD.TWO.AddDimTool.prototype.mousedown = function(e) {
 TCAD.TWO.AddDimTool.prototype.mousewheel = function(e) {
 };
 
+/** @constructor */
+TCAD.TWO.AddCircleDimTool = function(viewer, layer) {
+  this.viewer = viewer;
+  this.layer = layer;
+  this.dim = new TCAD.TWO.DiameterDimension(null);
+  this.viewer.add(this.dim, this.layer);
+};
+
+TCAD.TWO.AddCircleDimTool.prototype.keydown = function(e) {};
+TCAD.TWO.AddCircleDimTool.prototype.keypress = function(e) {};
+TCAD.TWO.AddCircleDimTool.prototype.keyup = function(e) {};
+TCAD.TWO.AddCircleDimTool.prototype.cleanup = function(e) {};
+
+TCAD.TWO.AddCircleDimTool.prototype.mousemove = function(e) {
+  var p = this.viewer.screenToModel(e);
+  var objects = this.viewer.search(p.x, p.y, 20 / this.viewer.scale, true, false, []);
+  var circles = objects.filter(function(o) {return o._class === 'TCAD.TWO.Circle'});
+  
+  if (circles.length != 0) {
+    this.dim.obj = circles[0];
+  } else {
+    this.dim.obj = null; 
+  }
+  if (this.dim.obj != null) {
+    this.dim.angle = Math.atan2(p.y - this.dim.obj.c.y, p.x - this.dim.obj.c.x);
+  }
+  this.viewer.refresh();
+};
+
+TCAD.TWO.AddCircleDimTool.prototype.mouseup = function(e) {
+  if (this.dim.obj !== null) {
+    this.viewer.historyManager.checkpoint();
+  } else {
+    this.viewer.remove(this.dim);
+  }
+  this.viewer.toolManager.releaseControl();
+};
+
+TCAD.TWO.AddCircleDimTool.prototype.mousedown = function(e) {
+};
+
+TCAD.TWO.AddCircleDimTool.prototype.mousewheel = function(e) {
+};
+
diff --git a/web/sketcher.html b/web/sketcher.html
index 0ff14793..9c66071a 100644
--- a/web/sketcher.html
+++ b/web/sketcher.html
@@ -65,7 +65,7 @@
     --><button class="btn tbtn act-addHDim" style="background-image: url(img/hdim.png);" type="submit" value=""></button><!--
     --><button class="btn tbtn act-addVDim" style="background-image: url(img/vdim.png);" type="submit" value=""></button><!--
     --><button class="btn tbtn act-addDim" style="background-image: url(img/dim.png);" type="submit" value=""></button><!--
-    --><button class="btn tbtn" style="background-image: url(img/ddim.png);" type="submit" value=""></button><!--
+    --><button class="btn tbtn act-addCircleDim" style="background-image: url(img/ddim.png);" type="submit" value=""></button><!--
     -->
   </div>
   <div style="width: 100%; height: calc(100% - 59px);">