diff --git a/debug/viewer.html b/debug/viewer.html
index b1d951648..b9d9d166f 100644
--- a/debug/viewer.html
+++ b/debug/viewer.html
@@ -36,6 +36,7 @@
     <script src="../src/core/intersect.js"></script>
     <script src="../src/models/BoltCircle.js"></script>
     <script src="../src/models/BoltRectangle.js"></script>
+    <script src="../src/models/Dome.js"></script>
     <script src="../src/models/RoundRectangle.js"></script>
     <script src="../src/models/Oval.js"></script>
     <script src="../src/models/OvalArc.js"></script>
@@ -62,7 +63,8 @@
         <label for="selectModelCode">model: </label>
         <select id="selectModelCode" onchange="Viewer.loadModelCode(this.value)">
             <option>polygonstackbox</option>
-            <option>stackbox</option>
+            <option>Rimbox</option>
+            <option>starbox</option>
             <option>combine</option>
             <option>logo</option>
             <option>smile</option>
diff --git a/debug/viewer.js b/debug/viewer.js
index 43161279c..c6faa1760 100644
--- a/debug/viewer.js
+++ b/debug/viewer.js
@@ -10,7 +10,7 @@ var Viewer = {
 
         //apply slider parameters
         if (typeof index !== 'undefined') {
-            Viewer.Params[index] = makerjs.round(arg, .001);
+            Viewer.Params[index] = arg;
         }
 
         var model = makerjs.kit.construct(Viewer.Constructor, Viewer.Params);
@@ -155,17 +155,35 @@ var Viewer = {
                 var label = new makerjs.exporter.XmlTag('label', { "for": id, title: attrs.title });
                 label.innerText = attrs.title + ': ';
 
-                if (attrs.type == 'range') {
-                    attrs.title = attrs.value;
-                    var input = new makerjs.exporter.XmlTag('input', attrs);
-                    input.attrs['onchange'] = 'this.title=this.value;Viewer.Refresh(' + i + ', this.valueAsNumber)';
-                    input.attrs['id'] = id;
+                var input = null;
 
-                    var div = new makerjs.exporter.XmlTag('div');
-                    div.innerText = label.toString() + input.toString();
-                    div.innerTextEscaped = true;
-                    paramsHtml += div.toString();
+                switch (attrs.type) {
+
+                    case 'range':
+                        attrs.title = attrs.value;
+                        input = new makerjs.exporter.XmlTag('input', attrs);
+                        input.attrs['onchange'] = 'this.title=this.value;Viewer.Refresh(' + i + ', makerjs.round(this.valueAsNumber, .001))';
+                        input.attrs['id'] = id;
+
+                        break;
+
+                    case 'bool':
+                        input = new makerjs.exporter.XmlTag('input', {
+                            id: id,
+                            type: 'checkbox',
+                            checked: attrs.value ? 'checked' : '',
+                            onchange: 'Viewer.Refresh(' + i + ', this.checked)'
+                        });
+
+                        break;
                 }
+
+                if (!input) continue;
+
+                var div = new makerjs.exporter.XmlTag('div');
+                div.innerText = label.toString() + input.toString();
+                div.innerTextEscaped = true;
+                paramsHtml += div.toString();
             }
         }
         document.getElementById("params").innerHTML = paramsHtml;
diff --git a/examples/Rimbox.js b/examples/Rimbox.js
new file mode 100644
index 000000000..f97eca0eb
--- /dev/null
+++ b/examples/Rimbox.js
@@ -0,0 +1,67 @@
+/// <reference path="typings/tsd.d.ts" />
+var makerjs = require('makerjs');
+var RimboxCorner = (function () {
+    function RimboxCorner(holeRadius, rimThickness) {
+        var rim = Math.min(rimThickness, holeRadius);
+        var hr = holeRadius + rim;
+        this.paths = {
+            centerRound: new makerjs.paths.Arc([0, 0], hr, 0, 90),
+            hFillet: new makerjs.paths.Arc([0, hr + holeRadius], holeRadius, 180, 270),
+            wFillet: new makerjs.paths.Arc([hr + holeRadius, 0], holeRadius, 180, 270)
+        };
+    }
+    return RimboxCorner;
+})();
+var RimboxInner = (function () {
+    function RimboxInner(width, height, holeRadius, rimThickness) {
+        var mm = makerjs.model;
+        var corner = new RimboxCorner(holeRadius, rimThickness);
+        this.models = {
+            bottomLeft: corner,
+            bottomRight: mm.move(mm.mirror(corner, true, false), [width, 0]),
+            topLeft: mm.move(mm.mirror(corner, false, true), [0, height]),
+            topRight: mm.move(mm.mirror(corner, true, true), [width, height])
+        };
+        var line = makerjs.paths.Line;
+        var rim = Math.min(rimThickness, holeRadius);
+        var d = 2 * holeRadius + rim;
+        this.paths = {
+            bottom: new line([d, -holeRadius], [width - d, -holeRadius]),
+            top: new line([d, height + holeRadius], [width - d, height + holeRadius]),
+            left: new line([-holeRadius, d], [-holeRadius, height - d]),
+            right: new line([width + holeRadius, d], [width + holeRadius, height - d])
+        };
+    }
+    return RimboxInner;
+})();
+var Rimbox = (function () {
+    function Rimbox(width, height, holeRadius, rimThickness, hollow) {
+        if (arguments.length == 0) {
+            var defaultValues = makerjs.kit.getParameterValues(Rimbox);
+            width = defaultValues.shift();
+            height = defaultValues.shift();
+            holeRadius = defaultValues.shift();
+            rimThickness = defaultValues.shift();
+        }
+        var mm = makerjs.models;
+        var cornerRadius = holeRadius + rimThickness;
+        var c2 = cornerRadius * 2;
+        this.models = {
+            bolts: new mm.BoltRectangle(width, height, holeRadius),
+            outer: new mm.RoundRectangle(width + c2, height + c2, cornerRadius)
+        };
+        if (hollow) {
+            this.models['inner'] = new RimboxInner(width, height, holeRadius, rimThickness);
+        }
+        this.models['outer'].origin = [-cornerRadius, -cornerRadius];
+    }
+    return Rimbox;
+})();
+Rimbox.metaParameters = [
+    { title: "width", type: "range", min: 10, max: 500, value: 120 },
+    { title: "height", type: "range", min: 10, max: 500, value: 100 },
+    { title: "holeRadius", type: "range", min: 1, max: 20, value: 3 },
+    { title: "rimThickness", type: "range", min: 1, max: 20, value: 2 },
+    { title: "hollow", type: "bool", value: true }
+];
+module.exports = Rimbox;
diff --git a/examples/combine.js b/examples/combine.js
index 8b9f19eed..969b1ef66 100644
--- a/examples/combine.js
+++ b/examples/combine.js
@@ -1,5 +1,5 @@
 
-function combine(angle) {
+function combine(angle, add) {
 
     var star1 = new makerjs.models.Oval(50, 100);
 
@@ -31,11 +31,12 @@ function combine(angle) {
         star2: star2
     };
 
-    makerjs.model.combine(star1, star2, false, true, false, true);
+    makerjs.model.combine(star1, star2, false, true, !add, add, add);
 }
 
 combine.metaParameters = [
-    { title: "angle", type: "range", min: -180, max: 180, step: 1, value: 40 }
+    { title: "angle", type: "range", min: -180, max: 180, step: 1, value: 40 },
+    { title: "add", type: "bool", value: true }
 ];
 
 
diff --git a/examples/stackbox.js b/examples/starbox.js
similarity index 82%
rename from examples/stackbox.js
rename to examples/starbox.js
index 410bd03ee..672bbdeb2 100644
--- a/examples/stackbox.js
+++ b/examples/starbox.js
@@ -1,7 +1,7 @@
 /// <reference path="typings/tsd.d.ts" />
 var makerjs = require('makerjs');
-var stackboxCorner = (function () {
-    function stackboxCorner(holeRadius, rimThickness) {
+var starboxCorner = (function () {
+    function starboxCorner(holeRadius, rimThickness) {
         var rim = Math.min(rimThickness, holeRadius);
         var hr = holeRadius + rim;
         this.paths = {
@@ -10,12 +10,12 @@ var stackboxCorner = (function () {
             wFillet: new makerjs.paths.Arc([hr + holeRadius, 0], holeRadius, 180, 270)
         };
     }
-    return stackboxCorner;
+    return starboxCorner;
 })();
-var stackboxInner = (function () {
-    function stackboxInner(width, height, holeRadius, rimThickness) {
+var starboxInner = (function () {
+    function starboxInner(width, height, holeRadius, rimThickness) {
         var mm = makerjs.model;
-        var corner = new stackboxCorner(holeRadius, rimThickness);
+        var corner = new starboxCorner(holeRadius, rimThickness);
         this.models = {
             bottomLeft: corner,
             bottomRight: mm.move(mm.mirror(corner, true, false), [width, 0]),
@@ -32,12 +32,12 @@ var stackboxInner = (function () {
             right: new line([width + holeRadius, d], [width + holeRadius, height - d])
         };
     }
-    return stackboxInner;
+    return starboxInner;
 })();
-var stackbox = (function () {
-    function stackbox(width, height, holeRadius, rimThickness, angle) {
+var starbox = (function () {
+    function starbox(width, height, holeRadius, rimThickness, angle) {
         if (arguments.length == 0) {
-            var defaultValues = makerjs.kit.getParameterValues(stackbox);
+            var defaultValues = makerjs.kit.getParameterValues(starbox);
             width = defaultValues.shift();
             height = defaultValues.shift();
             holeRadius = defaultValues.shift();
@@ -49,7 +49,7 @@ var stackbox = (function () {
         this.models = {
             bolts: new mm.BoltRectangle(width, height, holeRadius),
             outer: new mm.RoundRectangle(width + c2, height + c2, cornerRadius),
-            inner: new stackboxInner(width, height, holeRadius, rimThickness)
+            inner: new starboxInner(width, height, holeRadius, rimThickness)
         };
         this.models['outer'].origin = [-cornerRadius, -cornerRadius];
 
@@ -64,13 +64,13 @@ var stackbox = (function () {
 
         makerjs.model.combine(this.models.inner, star, false, true, true, false);
     }
-    return stackbox;
+    return starbox;
 })();
-stackbox.metaParameters = [
+starbox.metaParameters = [
     { title: "width", type: "range", min: 10, max: 500, value: 120 },
     { title: "height", type: "range", min: 10, max: 500, value: 100 },
     { title: "holeRadius", type: "range", min: 1, max: 20, value: 3 },
     { title: "rimThickness", type: "range", min: 1, max: 20, value: 2 },
     { title: "angle", type: "range", min: -180, max: 180, value: 45 }
 ];
-module.exports = stackbox;
+module.exports = starbox;
diff --git a/index.js b/index.js
index 09efe4f27..c963ba93a 100644
--- a/index.js
+++ b/index.js
@@ -568,10 +568,10 @@ var MakerJs;
          */
         var pathAreEqualMap = {};
         pathAreEqualMap[MakerJs.pathType.Line] = function (line1, line2) {
-            return MakerJs.point.areEqual(line1.end, line2.end);
+            return (MakerJs.point.areEqual(line1.origin, line2.origin) && MakerJs.point.areEqual(line1.end, line2.end)) || (MakerJs.point.areEqual(line1.origin, line2.end) && MakerJs.point.areEqual(line1.end, line2.origin));
         };
         pathAreEqualMap[MakerJs.pathType.Circle] = function (circle1, circle2) {
-            return circle1.radius == circle2.radius;
+            return MakerJs.point.areEqual(circle1.origin, circle2.origin) && circle1.radius == circle2.radius;
         };
         pathAreEqualMap[MakerJs.pathType.Arc] = function (arc1, arc2) {
             return pathAreEqualMap[MakerJs.pathType.Circle](arc1, arc2) && MakerJs.angle.areEqual(arc1.startAngle, arc2.startAngle) && MakerJs.angle.areEqual(arc1.endAngle, arc2.endAngle);
@@ -585,7 +585,7 @@ var MakerJs;
          */
         function areEqual(path1, path2) {
             var result = false;
-            if (path1.type == path2.type && MakerJs.point.areEqual(path1.origin, path2.origin)) {
+            if (path1.type == path2.type) {
                 var fn = pathAreEqualMap[path1.type];
                 if (fn) {
                     result = fn(path1, path2);
@@ -1139,7 +1139,7 @@ var MakerJs;
         function breakAlongForeignPath(segments, overlappedSegments, foreignPath) {
             if (MakerJs.path.areEqual(segments[0].path, foreignPath)) {
                 segments[0].overlapped = true;
-                segments[0].overlappedEqual = true;
+                segments[0].duplicate = true;
                 overlappedSegments.push(segments[0]);
                 return;
             }
@@ -1283,7 +1283,7 @@ var MakerJs;
         function checkForEqualOverlaps(crossedPathsA, crossedPathsB) {
             function compareSegments(segment1, segment2) {
                 if (MakerJs.path.areEqual(segment1.path, segment2.path)) {
-                    segment1.overlappedEqual = segment2.overlappedEqual = true;
+                    segment1.duplicate = segment2.duplicate = true;
                 }
             }
             function compareAll(segment) {
@@ -1298,7 +1298,7 @@ var MakerJs;
         /**
          * @private
          */
-        function addOrDeleteSegments(crossedPath, includeInside, includeOutside, firstPass) {
+        function addOrDeleteSegments(crossedPath, includeInside, includeOutside, keepDuplicates) {
             function addSegment(model, pathIdBase, segment) {
                 var id = model_1.getSimilarPathId(model, pathIdBase);
                 model.paths[id] = segment.path;
@@ -1311,8 +1311,8 @@ var MakerJs;
             //delete the original, its segments will be added
             delete crossedPath.modelContext.paths[crossedPath.pathId];
             for (var i = 0; i < crossedPath.segments.length; i++) {
-                if (crossedPath.segments[i].overlappedEqual) {
-                    if (firstPass) {
+                if (crossedPath.segments[i].duplicate) {
+                    if (keepDuplicates) {
                         addSegment(crossedPath.modelContext, crossedPath.pathId, crossedPath.segments[i]);
                     }
                 }
@@ -1330,14 +1330,16 @@ var MakerJs;
          * @param includeAOutsideB Flag to include paths from modelA which are outside of modelB.
          * @param includeBInsideA Flag to include paths from modelB which are inside of modelA.
          * @param includeBOutsideA Flag to include paths from modelB which are outside of modelA.
+         * @param keepDuplicates Flag to include paths which are duplicate in both models.
          * @param farPoint Optional point of reference which is outside the bounds of both models.
          */
-        function combine(modelA, modelB, includeAInsideB, includeAOutsideB, includeBInsideA, includeBOutsideA, farPoint) {
+        function combine(modelA, modelB, includeAInsideB, includeAOutsideB, includeBInsideA, includeBOutsideA, keepDuplicates, farPoint) {
+            if (keepDuplicates === void 0) { keepDuplicates = true; }
             var pathsA = breakAllPathsAtIntersections(modelA, modelB, farPoint);
             var pathsB = breakAllPathsAtIntersections(modelB, modelA, farPoint);
             checkForEqualOverlaps(pathsA.overlappedSegments, pathsB.overlappedSegments);
             for (var i = 0; i < pathsA.crossedPaths.length; i++) {
-                addOrDeleteSegments(pathsA.crossedPaths[i], includeAInsideB, includeAOutsideB, true);
+                addOrDeleteSegments(pathsA.crossedPaths[i], includeAInsideB, includeAOutsideB, keepDuplicates);
             }
             for (var i = 0; i < pathsB.crossedPaths.length; i++) {
                 addOrDeleteSegments(pathsB.crossedPaths[i], includeBInsideA, includeBOutsideA);
@@ -3383,6 +3385,35 @@ var MakerJs;
     })(models = MakerJs.models || (MakerJs.models = {}));
 })(MakerJs || (MakerJs = {}));
 var MakerJs;
+(function (MakerJs) {
+    var models;
+    (function (models) {
+        var Dome = (function () {
+            function Dome(width, height, radius) {
+                if (radius === void 0) { radius = Math.min(width / 2, height); }
+                this.paths = {};
+                var w2 = width / 2;
+                var wt = Math.max(w2 - radius, 0);
+                var hr = Math.max(height - radius, 0);
+                this.paths["Bottom"] = new MakerJs.paths.Line([-w2, 0], [w2, 0]);
+                if (hr) {
+                    this.paths["Left"] = new MakerJs.paths.Line([-w2, 0], [-w2, hr]);
+                    this.paths["Right"] = new MakerJs.paths.Line([w2, 0], [w2, hr]);
+                }
+                if (radius > 0) {
+                    this.paths["TopLeft"] = new MakerJs.paths.Arc([-wt, hr], radius, 90, 180);
+                    this.paths["TopRight"] = new MakerJs.paths.Arc([wt, hr], radius, 0, 90);
+                }
+                if (wt) {
+                    this.paths["Top"] = new MakerJs.paths.Line([-wt, height], [wt, height]);
+                }
+            }
+            return Dome;
+        })();
+        models.Dome = Dome;
+    })(models = MakerJs.models || (MakerJs.models = {}));
+})(MakerJs || (MakerJs = {}));
+var MakerJs;
 (function (MakerJs) {
     var models;
     (function (models) {
diff --git a/package.json b/package.json
index e451c25fa..e44857c8b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "makerjs",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "description": "Maker.js, a Microsoft Garage project, is a JavaScript library for creating and sharing modular line drawings for CNC and laser cutters.",
   "main": "index.js",
   "scripts": {
diff --git a/src/core/combine.ts b/src/core/combine.ts
index 91757fd6c..d8ee127d7 100644
--- a/src/core/combine.ts
+++ b/src/core/combine.ts
@@ -28,7 +28,7 @@ module MakerJs.model {
 
         if (path.areEqual(segments[0].path, foreignPath)) {
             segments[0].overlapped = true;
-            segments[0].overlappedEqual = true;
+            segments[0].duplicate = true;
 
             overlappedSegments.push(segments[0]);
             return;
@@ -172,7 +172,7 @@ module MakerJs.model {
      */
     interface ICrossedPathSegment extends IPathInside {
         overlapped: boolean;
-        overlappedEqual?: boolean;
+        duplicate?: boolean;
     }
 
     /**
@@ -242,7 +242,7 @@ module MakerJs.model {
 
         function compareSegments(segment1: ICrossedPathSegment, segment2: ICrossedPathSegment) {
             if (path.areEqual(segment1.path, segment2.path)) {
-                segment1.overlappedEqual = segment2.overlappedEqual = true;
+                segment1.duplicate = segment2.duplicate = true;
             }
         }
 
@@ -261,7 +261,7 @@ module MakerJs.model {
     /**
      * @private
      */
-    function addOrDeleteSegments(crossedPath: ICrossedPath, includeInside: boolean, includeOutside: boolean, firstPass?: boolean) {
+    function addOrDeleteSegments(crossedPath: ICrossedPath, includeInside: boolean, includeOutside: boolean, keepDuplicates?: boolean) {
 
         function addSegment(model: IModel, pathIdBase: string, segment: ICrossedPathSegment) {
             var id = getSimilarPathId(model, pathIdBase);
@@ -278,8 +278,8 @@ module MakerJs.model {
         delete crossedPath.modelContext.paths[crossedPath.pathId];
 
         for (var i = 0; i < crossedPath.segments.length; i++) {
-            if (crossedPath.segments[i].overlappedEqual) {
-                if (firstPass) {
+            if (crossedPath.segments[i].duplicate) {
+                if (keepDuplicates) {
                     addSegment(crossedPath.modelContext, crossedPath.pathId, crossedPath.segments[i]);
                 }
             } else {
@@ -297,9 +297,10 @@ module MakerJs.model {
      * @param includeAOutsideB Flag to include paths from modelA which are outside of modelB.
      * @param includeBInsideA Flag to include paths from modelB which are inside of modelA.
      * @param includeBOutsideA Flag to include paths from modelB which are outside of modelA.
+     * @param keepDuplicates Flag to include paths which are duplicate in both models.
      * @param farPoint Optional point of reference which is outside the bounds of both models.
      */
-    export function combine(modelA: IModel, modelB: IModel, includeAInsideB: boolean, includeAOutsideB: boolean, includeBInsideA: boolean, includeBOutsideA: boolean, farPoint?: IPoint) {
+    export function combine(modelA: IModel, modelB: IModel, includeAInsideB: boolean, includeAOutsideB: boolean, includeBInsideA: boolean, includeBOutsideA: boolean, keepDuplicates: boolean = true, farPoint?: IPoint) {
 
         var pathsA = breakAllPathsAtIntersections(modelA, modelB, farPoint);
         var pathsB = breakAllPathsAtIntersections(modelB, modelA, farPoint);
@@ -307,7 +308,7 @@ module MakerJs.model {
         checkForEqualOverlaps(pathsA.overlappedSegments, pathsB.overlappedSegments);
 
         for (var i = 0; i < pathsA.crossedPaths.length; i++) {
-            addOrDeleteSegments(pathsA.crossedPaths[i], includeAInsideB, includeAOutsideB, true);
+            addOrDeleteSegments(pathsA.crossedPaths[i], includeAInsideB, includeAOutsideB, keepDuplicates);
         }
 
         for (var i = 0; i < pathsB.crossedPaths.length; i++) {
diff --git a/src/core/path.ts b/src/core/path.ts
index a09de1390..09d24e3de 100644
--- a/src/core/path.ts
+++ b/src/core/path.ts
@@ -15,11 +15,11 @@ module MakerJs.path {
     var pathAreEqualMap: IPathAreEqualMap = {};
 
     pathAreEqualMap[pathType.Line] = function (line1: IPathLine, line2: IPathLine): boolean {
-        return point.areEqual(line1.end, line2.end);
+        return (point.areEqual(line1.origin, line2.origin) && point.areEqual(line1.end, line2.end)) || (point.areEqual(line1.origin, line2.end) && point.areEqual(line1.end, line2.origin));
     };
 
     pathAreEqualMap[pathType.Circle] = function (circle1: IPathCircle, circle2: IPathCircle): boolean {
-        return circle1.radius == circle2.radius;
+        return point.areEqual(circle1.origin, circle2.origin) && circle1.radius == circle2.radius;
     };
 
     pathAreEqualMap[pathType.Arc] = function (arc1: IPathArc, arc2: IPathArc): boolean {
@@ -37,13 +37,11 @@ module MakerJs.path {
 
         var result = false;
 
-        if (path1.type == path2.type && point.areEqual(path1.origin, path2.origin)) {
-
+        if (path1.type == path2.type) {
             var fn = pathAreEqualMap[path1.type];
             if (fn) {
                 result = fn(path1, path2);
             }
-
         }
 
         return result;
diff --git a/src/models/Dome.ts b/src/models/Dome.ts
new file mode 100644
index 000000000..3bfcaa512
--- /dev/null
+++ b/src/models/Dome.ts
@@ -0,0 +1,31 @@
+module MakerJs.models {
+
+    export class Dome implements IModel {
+
+        public paths: IPathMap = {};
+
+        constructor(width: number, height: number, radius: number = Math.min(width / 2, height)) {
+
+            var w2 = width / 2;
+            var wt = Math.max(w2 - radius, 0);
+            var hr = Math.max(height - radius, 0);
+
+            this.paths["Bottom"] = new paths.Line([-w2, 0], [w2, 0]);
+
+            if (hr) {
+                this.paths["Left"] = new paths.Line([-w2, 0], [-w2, hr]);
+                this.paths["Right"] = new paths.Line([w2, 0], [w2, hr]);
+            }
+
+            if (radius > 0) {
+                this.paths["TopLeft"] = new paths.Arc([-wt, hr], radius, 90, 180);
+                this.paths["TopRight"] = new paths.Arc([wt, hr], radius, 0, 90);
+            }
+
+            if (wt) {
+                this.paths["Top"] = new paths.Line([-wt, height], [wt, height]);
+            }
+
+        }
+    }
+}
diff --git a/target/js/browser.maker.js b/target/js/browser.maker.js
index 2de6baa8a..732889937 100644
--- a/target/js/browser.maker.js
+++ b/target/js/browser.maker.js
@@ -569,10 +569,10 @@ var MakerJs;
          */
         var pathAreEqualMap = {};
         pathAreEqualMap[MakerJs.pathType.Line] = function (line1, line2) {
-            return MakerJs.point.areEqual(line1.end, line2.end);
+            return (MakerJs.point.areEqual(line1.origin, line2.origin) && MakerJs.point.areEqual(line1.end, line2.end)) || (MakerJs.point.areEqual(line1.origin, line2.end) && MakerJs.point.areEqual(line1.end, line2.origin));
         };
         pathAreEqualMap[MakerJs.pathType.Circle] = function (circle1, circle2) {
-            return circle1.radius == circle2.radius;
+            return MakerJs.point.areEqual(circle1.origin, circle2.origin) && circle1.radius == circle2.radius;
         };
         pathAreEqualMap[MakerJs.pathType.Arc] = function (arc1, arc2) {
             return pathAreEqualMap[MakerJs.pathType.Circle](arc1, arc2) && MakerJs.angle.areEqual(arc1.startAngle, arc2.startAngle) && MakerJs.angle.areEqual(arc1.endAngle, arc2.endAngle);
@@ -586,7 +586,7 @@ var MakerJs;
          */
         function areEqual(path1, path2) {
             var result = false;
-            if (path1.type == path2.type && MakerJs.point.areEqual(path1.origin, path2.origin)) {
+            if (path1.type == path2.type) {
                 var fn = pathAreEqualMap[path1.type];
                 if (fn) {
                     result = fn(path1, path2);
@@ -1140,7 +1140,7 @@ var MakerJs;
         function breakAlongForeignPath(segments, overlappedSegments, foreignPath) {
             if (MakerJs.path.areEqual(segments[0].path, foreignPath)) {
                 segments[0].overlapped = true;
-                segments[0].overlappedEqual = true;
+                segments[0].duplicate = true;
                 overlappedSegments.push(segments[0]);
                 return;
             }
@@ -1284,7 +1284,7 @@ var MakerJs;
         function checkForEqualOverlaps(crossedPathsA, crossedPathsB) {
             function compareSegments(segment1, segment2) {
                 if (MakerJs.path.areEqual(segment1.path, segment2.path)) {
-                    segment1.overlappedEqual = segment2.overlappedEqual = true;
+                    segment1.duplicate = segment2.duplicate = true;
                 }
             }
             function compareAll(segment) {
@@ -1299,7 +1299,7 @@ var MakerJs;
         /**
          * @private
          */
-        function addOrDeleteSegments(crossedPath, includeInside, includeOutside, firstPass) {
+        function addOrDeleteSegments(crossedPath, includeInside, includeOutside, keepDuplicates) {
             function addSegment(model, pathIdBase, segment) {
                 var id = model_1.getSimilarPathId(model, pathIdBase);
                 model.paths[id] = segment.path;
@@ -1312,8 +1312,8 @@ var MakerJs;
             //delete the original, its segments will be added
             delete crossedPath.modelContext.paths[crossedPath.pathId];
             for (var i = 0; i < crossedPath.segments.length; i++) {
-                if (crossedPath.segments[i].overlappedEqual) {
-                    if (firstPass) {
+                if (crossedPath.segments[i].duplicate) {
+                    if (keepDuplicates) {
                         addSegment(crossedPath.modelContext, crossedPath.pathId, crossedPath.segments[i]);
                     }
                 }
@@ -1331,14 +1331,16 @@ var MakerJs;
          * @param includeAOutsideB Flag to include paths from modelA which are outside of modelB.
          * @param includeBInsideA Flag to include paths from modelB which are inside of modelA.
          * @param includeBOutsideA Flag to include paths from modelB which are outside of modelA.
+         * @param keepDuplicates Flag to include paths which are duplicate in both models.
          * @param farPoint Optional point of reference which is outside the bounds of both models.
          */
-        function combine(modelA, modelB, includeAInsideB, includeAOutsideB, includeBInsideA, includeBOutsideA, farPoint) {
+        function combine(modelA, modelB, includeAInsideB, includeAOutsideB, includeBInsideA, includeBOutsideA, keepDuplicates, farPoint) {
+            if (keepDuplicates === void 0) { keepDuplicates = true; }
             var pathsA = breakAllPathsAtIntersections(modelA, modelB, farPoint);
             var pathsB = breakAllPathsAtIntersections(modelB, modelA, farPoint);
             checkForEqualOverlaps(pathsA.overlappedSegments, pathsB.overlappedSegments);
             for (var i = 0; i < pathsA.crossedPaths.length; i++) {
-                addOrDeleteSegments(pathsA.crossedPaths[i], includeAInsideB, includeAOutsideB, true);
+                addOrDeleteSegments(pathsA.crossedPaths[i], includeAInsideB, includeAOutsideB, keepDuplicates);
             }
             for (var i = 0; i < pathsB.crossedPaths.length; i++) {
                 addOrDeleteSegments(pathsB.crossedPaths[i], includeBInsideA, includeBOutsideA);
@@ -3384,6 +3386,35 @@ var MakerJs;
     })(models = MakerJs.models || (MakerJs.models = {}));
 })(MakerJs || (MakerJs = {}));
 var MakerJs;
+(function (MakerJs) {
+    var models;
+    (function (models) {
+        var Dome = (function () {
+            function Dome(width, height, radius) {
+                if (radius === void 0) { radius = Math.min(width / 2, height); }
+                this.paths = {};
+                var w2 = width / 2;
+                var wt = Math.max(w2 - radius, 0);
+                var hr = Math.max(height - radius, 0);
+                this.paths["Bottom"] = new MakerJs.paths.Line([-w2, 0], [w2, 0]);
+                if (hr) {
+                    this.paths["Left"] = new MakerJs.paths.Line([-w2, 0], [-w2, hr]);
+                    this.paths["Right"] = new MakerJs.paths.Line([w2, 0], [w2, hr]);
+                }
+                if (radius > 0) {
+                    this.paths["TopLeft"] = new MakerJs.paths.Arc([-wt, hr], radius, 90, 180);
+                    this.paths["TopRight"] = new MakerJs.paths.Arc([wt, hr], radius, 0, 90);
+                }
+                if (wt) {
+                    this.paths["Top"] = new MakerJs.paths.Line([-wt, height], [wt, height]);
+                }
+            }
+            return Dome;
+        })();
+        models.Dome = Dome;
+    })(models = MakerJs.models || (MakerJs.models = {}));
+})(MakerJs || (MakerJs = {}));
+var MakerJs;
 (function (MakerJs) {
     var models;
     (function (models) {
diff --git a/target/js/node.maker.js b/target/js/node.maker.js
index 09efe4f27..c963ba93a 100644
--- a/target/js/node.maker.js
+++ b/target/js/node.maker.js
@@ -568,10 +568,10 @@ var MakerJs;
          */
         var pathAreEqualMap = {};
         pathAreEqualMap[MakerJs.pathType.Line] = function (line1, line2) {
-            return MakerJs.point.areEqual(line1.end, line2.end);
+            return (MakerJs.point.areEqual(line1.origin, line2.origin) && MakerJs.point.areEqual(line1.end, line2.end)) || (MakerJs.point.areEqual(line1.origin, line2.end) && MakerJs.point.areEqual(line1.end, line2.origin));
         };
         pathAreEqualMap[MakerJs.pathType.Circle] = function (circle1, circle2) {
-            return circle1.radius == circle2.radius;
+            return MakerJs.point.areEqual(circle1.origin, circle2.origin) && circle1.radius == circle2.radius;
         };
         pathAreEqualMap[MakerJs.pathType.Arc] = function (arc1, arc2) {
             return pathAreEqualMap[MakerJs.pathType.Circle](arc1, arc2) && MakerJs.angle.areEqual(arc1.startAngle, arc2.startAngle) && MakerJs.angle.areEqual(arc1.endAngle, arc2.endAngle);
@@ -585,7 +585,7 @@ var MakerJs;
          */
         function areEqual(path1, path2) {
             var result = false;
-            if (path1.type == path2.type && MakerJs.point.areEqual(path1.origin, path2.origin)) {
+            if (path1.type == path2.type) {
                 var fn = pathAreEqualMap[path1.type];
                 if (fn) {
                     result = fn(path1, path2);
@@ -1139,7 +1139,7 @@ var MakerJs;
         function breakAlongForeignPath(segments, overlappedSegments, foreignPath) {
             if (MakerJs.path.areEqual(segments[0].path, foreignPath)) {
                 segments[0].overlapped = true;
-                segments[0].overlappedEqual = true;
+                segments[0].duplicate = true;
                 overlappedSegments.push(segments[0]);
                 return;
             }
@@ -1283,7 +1283,7 @@ var MakerJs;
         function checkForEqualOverlaps(crossedPathsA, crossedPathsB) {
             function compareSegments(segment1, segment2) {
                 if (MakerJs.path.areEqual(segment1.path, segment2.path)) {
-                    segment1.overlappedEqual = segment2.overlappedEqual = true;
+                    segment1.duplicate = segment2.duplicate = true;
                 }
             }
             function compareAll(segment) {
@@ -1298,7 +1298,7 @@ var MakerJs;
         /**
          * @private
          */
-        function addOrDeleteSegments(crossedPath, includeInside, includeOutside, firstPass) {
+        function addOrDeleteSegments(crossedPath, includeInside, includeOutside, keepDuplicates) {
             function addSegment(model, pathIdBase, segment) {
                 var id = model_1.getSimilarPathId(model, pathIdBase);
                 model.paths[id] = segment.path;
@@ -1311,8 +1311,8 @@ var MakerJs;
             //delete the original, its segments will be added
             delete crossedPath.modelContext.paths[crossedPath.pathId];
             for (var i = 0; i < crossedPath.segments.length; i++) {
-                if (crossedPath.segments[i].overlappedEqual) {
-                    if (firstPass) {
+                if (crossedPath.segments[i].duplicate) {
+                    if (keepDuplicates) {
                         addSegment(crossedPath.modelContext, crossedPath.pathId, crossedPath.segments[i]);
                     }
                 }
@@ -1330,14 +1330,16 @@ var MakerJs;
          * @param includeAOutsideB Flag to include paths from modelA which are outside of modelB.
          * @param includeBInsideA Flag to include paths from modelB which are inside of modelA.
          * @param includeBOutsideA Flag to include paths from modelB which are outside of modelA.
+         * @param keepDuplicates Flag to include paths which are duplicate in both models.
          * @param farPoint Optional point of reference which is outside the bounds of both models.
          */
-        function combine(modelA, modelB, includeAInsideB, includeAOutsideB, includeBInsideA, includeBOutsideA, farPoint) {
+        function combine(modelA, modelB, includeAInsideB, includeAOutsideB, includeBInsideA, includeBOutsideA, keepDuplicates, farPoint) {
+            if (keepDuplicates === void 0) { keepDuplicates = true; }
             var pathsA = breakAllPathsAtIntersections(modelA, modelB, farPoint);
             var pathsB = breakAllPathsAtIntersections(modelB, modelA, farPoint);
             checkForEqualOverlaps(pathsA.overlappedSegments, pathsB.overlappedSegments);
             for (var i = 0; i < pathsA.crossedPaths.length; i++) {
-                addOrDeleteSegments(pathsA.crossedPaths[i], includeAInsideB, includeAOutsideB, true);
+                addOrDeleteSegments(pathsA.crossedPaths[i], includeAInsideB, includeAOutsideB, keepDuplicates);
             }
             for (var i = 0; i < pathsB.crossedPaths.length; i++) {
                 addOrDeleteSegments(pathsB.crossedPaths[i], includeBInsideA, includeBOutsideA);
@@ -3383,6 +3385,35 @@ var MakerJs;
     })(models = MakerJs.models || (MakerJs.models = {}));
 })(MakerJs || (MakerJs = {}));
 var MakerJs;
+(function (MakerJs) {
+    var models;
+    (function (models) {
+        var Dome = (function () {
+            function Dome(width, height, radius) {
+                if (radius === void 0) { radius = Math.min(width / 2, height); }
+                this.paths = {};
+                var w2 = width / 2;
+                var wt = Math.max(w2 - radius, 0);
+                var hr = Math.max(height - radius, 0);
+                this.paths["Bottom"] = new MakerJs.paths.Line([-w2, 0], [w2, 0]);
+                if (hr) {
+                    this.paths["Left"] = new MakerJs.paths.Line([-w2, 0], [-w2, hr]);
+                    this.paths["Right"] = new MakerJs.paths.Line([w2, 0], [w2, hr]);
+                }
+                if (radius > 0) {
+                    this.paths["TopLeft"] = new MakerJs.paths.Arc([-wt, hr], radius, 90, 180);
+                    this.paths["TopRight"] = new MakerJs.paths.Arc([wt, hr], radius, 0, 90);
+                }
+                if (wt) {
+                    this.paths["Top"] = new MakerJs.paths.Line([-wt, height], [wt, height]);
+                }
+            }
+            return Dome;
+        })();
+        models.Dome = Dome;
+    })(models = MakerJs.models || (MakerJs.models = {}));
+})(MakerJs || (MakerJs = {}));
+var MakerJs;
 (function (MakerJs) {
     var models;
     (function (models) {
diff --git a/target/ts/makerjs.d.ts b/target/ts/makerjs.d.ts
index 8ed3d2ecf..3e2b16a8c 100644
--- a/target/ts/makerjs.d.ts
+++ b/target/ts/makerjs.d.ts
@@ -772,9 +772,10 @@ declare module MakerJs.model {
      * @param includeAOutsideB Flag to include paths from modelA which are outside of modelB.
      * @param includeBInsideA Flag to include paths from modelB which are inside of modelA.
      * @param includeBOutsideA Flag to include paths from modelB which are outside of modelA.
+     * @param keepDuplicates Flag to include paths which are duplicate in both models.
      * @param farPoint Optional point of reference which is outside the bounds of both models.
      */
-    function combine(modelA: IModel, modelB: IModel, includeAInsideB: boolean, includeAOutsideB: boolean, includeBInsideA: boolean, includeBOutsideA: boolean, farPoint?: IPoint): void;
+    function combine(modelA: IModel, modelB: IModel, includeAInsideB: boolean, includeAOutsideB: boolean, includeBInsideA: boolean, includeBOutsideA: boolean, keepDuplicates?: boolean, farPoint?: IPoint): void;
 }
 declare module MakerJs.units {
     /**
@@ -1202,6 +1203,12 @@ declare module MakerJs.models {
         constructor(width: number, height: number, holeRadius: number);
     }
 }
+declare module MakerJs.models {
+    class Dome implements IModel {
+        paths: IPathMap;
+        constructor(width: number, height: number, radius?: number);
+    }
+}
 declare module MakerJs.models {
     class RoundRectangle implements IModel {
         paths: IPathMap;