diff --git a/web/app/sketcher/shapes/dim.js b/web/app/sketcher/shapes/dim.js
index b2a95d81..98e7085a 100644
--- a/web/app/sketcher/shapes/dim.js
+++ b/web/app/sketcher/shapes/dim.js
@@ -1,6 +1,6 @@
 import * as utils from '../../utils/utils'
 import * as math from '../../math/math'
-import {SketchObject, EndPoint} from '../viewer2d'
+import {SketchObject} from '../viewer2d'
 import Vector from '../../math/vector'
 
 /** @constructor */
@@ -297,106 +297,4 @@ DiameterDimension.prototype.normalDistance = function(aim) {
   return -1;
 };
 
-/** @constructor */
-function AddDimTool(viewer, layer, dimCreation) {
-  this.viewer = viewer;
-  this.layer = layer;
-  this.dim = null;
-  this._v = new Vector(0, 0, 0);
-  this.dimCreation = dimCreation;
-}
-
-AddDimTool.prototype.keydown = function(e) {};
-AddDimTool.prototype.keypress = function(e) {};
-AddDimTool.prototype.keyup = function(e) {};
-AddDimTool.prototype.cleanup = function(e) {};
-
-AddDimTool.prototype.mousemove = function(e) {
-  var p = this.viewer.screenToModel(e);
-  this.viewer.snap(p.x, p.y, []);
-  if (this.dim != null) {
-    this.dim.b.x = p.x;
-    this.dim.b.y = p.y;
-  }
-  this.viewer.refresh();
-};
-
-AddDimTool.prototype.mouseup = function(e) {
-
-  if (e.button > 0 && this.dim != null) {
-    this.dim.flip = !this.dim.flip;
-    this.viewer.refresh();
-    return;
-  }
-
-  if (this.viewer.snapped.length == 0) {
-    return;
-  }
-
-  var p = this.viewer.snapped.pop();
-  this.viewer.cleanSnap();
-
-  if (this.dim == null) {
-    this.viewer.historyManager.checkpoint();
-    this.dim = this.dimCreation(p, new EndPoint(p.x, p.y));
-    this.layer.objects.push(this.dim);
-    this.viewer.refresh();
-  } else {
-    this.dim.b = p;
-    this.viewer.toolManager.releaseControl();
-    this.viewer.refresh();
-  }
-};
-
-AddDimTool.prototype.mousedown = function(e) {
-};
-
-AddDimTool.prototype.mousewheel = function(e) {
-};
-
-/** @constructor */
-function AddCircleDimTool(viewer, layer) {
-  this.viewer = viewer;
-  this.layer = layer;
-  this.dim = new DiameterDimension(null);
-  this.viewer.add(this.dim, this.layer);
-}
-
-AddCircleDimTool.prototype.keydown = function(e) {};
-AddCircleDimTool.prototype.keypress = function(e) {};
-AddCircleDimTool.prototype.keyup = function(e) {};
-AddCircleDimTool.prototype.cleanup = function(e) {};
-
-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, []).filter(function(o) {
-    return o._class === 'TCAD.TWO.Circle' || o._class === 'TCAD.TWO.Arc'; 
-  });
-  
-  if (objects.length != 0) {
-    this.dim.obj = objects[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();
-};
-
-AddCircleDimTool.prototype.mouseup = function(e) {
-  if (this.dim.obj !== null) {
-    this.viewer.historyManager.checkpoint();
-  } else {
-    this.viewer.remove(this.dim);
-  }
-  this.viewer.toolManager.releaseControl();
-};
-
-AddCircleDimTool.prototype.mousedown = function(e) {
-};
-
-AddCircleDimTool.prototype.mousewheel = function(e) {
-};
-
-export {AddDimTool, AddCircleDimTool, HDimension, VDimension, Dimension, DiameterDimension}
+export {HDimension, VDimension, Dimension, DiameterDimension}
diff --git a/web/app/sketcher/sketcher-app.js b/web/app/sketcher/sketcher-app.js
index 5806da56..c1a02c07 100644
--- a/web/app/sketcher/sketcher-app.js
+++ b/web/app/sketcher/sketcher-app.js
@@ -2,7 +2,7 @@ import {Viewer} from './viewer2d.js'
 import * as ui from '../ui/ui'
 import {Terminal} from '../ui/terminal'
 import {IO, BBox} from './io'
-import {AddDimTool, AddCircleDimTool, HDimension, VDimension, Dimension, DiameterDimension} from './shapes/dim'
+import {AddFreeDimTool, AddHorizontalDimTool, AddVerticalDimTool, AddCircleDimTool} from './tools/dim'
 import {AddPointTool} from './tools/point'
 import {AddSegmentTool} from './tools/segment'
 import {AddArcTool} from './tools/arc'
@@ -11,7 +11,6 @@ import {FilletTool} from './helpers'
 import {ReferencePointTool} from './tools/origin'
 import {InputManager} from './input-manager'
 
-/** @constructor */
 function App2D() {
   var app = this;
 
@@ -144,15 +143,15 @@ function App2D() {
   });
 
   this.registerAction('addDim', "Add Dimension", function () {
-    app.viewer.toolManager.takeControl(new AddDimTool(app.viewer, app.viewer.dimLayer, function(a,b) {return new Dimension(a,b)} ));
+    app.viewer.toolManager.takeControl(new AddFreeDimTool(app.viewer, app.viewer.dimLayer));
   });
   
   this.registerAction('addHDim', "Add Horizontal Dimension", function () {
-    app.viewer.toolManager.takeControl(new AddDimTool(app.viewer, app.viewer.dimLayer, function(a,b) {return new HDimension(a,b)} ));
+    app.viewer.toolManager.takeControl(new AddHorizontalDimTool(app.viewer, app.viewer.dimLayer));
   });
   
   this.registerAction('addVDim', "Add Vertical Dimension", function () {
-    app.viewer.toolManager.takeControl(new AddDimTool(app.viewer, app.viewer.dimLayer, function(a,b) {return new VDimension(a,b)} ));
+    app.viewer.toolManager.takeControl(new AddVerticalDimTool(app.viewer, app.viewer.dimLayer));
   });
 
   this.registerAction('addCircleDim', "Add Circle Dimension", function () {
diff --git a/web/app/sketcher/tools/dim.js b/web/app/sketcher/tools/dim.js
new file mode 100644
index 00000000..b6e241cf
--- /dev/null
+++ b/web/app/sketcher/tools/dim.js
@@ -0,0 +1,106 @@
+import {HDimension, VDimension, Dimension, DiameterDimension} from '../shapes/dim'
+import Vector from '../../math/vector'
+import {EndPoint} from '../viewer2d'
+import {Tool} from './tool'
+
+export class AddDimTool extends Tool {
+
+  constructor(name, viewer, layer, dimCreation) {
+    super(name, viewer);
+    this.layer = layer;
+    this.dim = null;
+    this._v = new Vector(0, 0, 0);
+    this.dimCreation = dimCreation;
+  }
+
+  mousemove(e) {
+    var p = this.viewer.screenToModel(e);
+    this.viewer.snap(p.x, p.y, []);
+    if (this.dim != null) {
+      this.dim.b.x = p.x;
+      this.dim.b.y = p.y;
+    }
+    this.viewer.refresh();
+  }
+
+  mouseup(e) {
+
+    if (e.button > 0 && this.dim != null) {
+      this.dim.flip = !this.dim.flip;
+      this.viewer.refresh();
+      return;
+    }
+
+    if (this.viewer.snapped.length == 0) {
+      return;
+    }
+
+    var p = this.viewer.snapped.pop();
+    this.viewer.cleanSnap();
+
+    if (this.dim == null) {
+      this.viewer.historyManager.checkpoint();
+      this.dim = this.dimCreation(p, new EndPoint(p.x, p.y));
+      this.layer.objects.push(this.dim);
+      this.viewer.refresh();
+    } else {
+      this.dim.b = p;
+      this.viewer.toolManager.releaseControl();
+      this.viewer.refresh();
+    }
+  }
+}
+
+export class AddFreeDimTool extends AddDimTool {
+  constructor(viewer, layer) {
+    super('free dimension', viewer, layer, (a, b) => new Dimension(a, b));
+  }
+}
+
+export class AddHorizontalDimTool extends AddDimTool {
+  constructor(viewer, layer) {
+    super('horizontal dimension', viewer, layer, (a, b) => new HDimension(a, b));
+  }
+}
+
+export class AddVerticalDimTool extends AddDimTool {
+  constructor(viewer, layer) {
+    super('vertical dimension', viewer, layer, (a, b) => new VDimension(a, b));
+  }
+}
+
+export class AddCircleDimTool extends Tool {
+  constructor(viewer, layer) {
+    super(viewer);
+    this.layer = layer;
+    this.dim = new DiameterDimension(null);
+    this.viewer.add(this.dim, this.layer);
+  }
+
+  mousemove(e) {
+    var p = this.viewer.screenToModel(e);
+    var objects = this.viewer.search(p.x, p.y, 20 / this.viewer.scale, true, false, []).filter(function (o) {
+      return o._class === 'TCAD.TWO.Circle' || o._class === 'TCAD.TWO.Arc';
+    });
+
+    if (objects.length != 0) {
+      this.dim.obj = objects[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();
+  }
+
+  mouseup(e) {
+    if (this.dim.obj !== null) {
+      this.viewer.historyManager.checkpoint();
+    } else {
+      this.viewer.remove(this.dim);
+    }
+    this.viewer.toolManager.releaseControl();
+  }
+}
+