diff --git a/lib/network/modules/PhysicsEngine.js b/lib/network/modules/PhysicsEngine.js
index ff13ccb0..9f8fa20c 100644
--- a/lib/network/modules/PhysicsEngine.js
+++ b/lib/network/modules/PhysicsEngine.js
@@ -90,6 +90,8 @@ class PhysicsEngine {
     this.timestep = 0.5;
     this.layoutFailed = false;
     this.draggingNodes = [];
+    this.positionUpdateHandler = () => {};
+    this.physicsUpdateHandler = () => {};
 
     this.bindEventListeners();
   }
@@ -115,6 +117,8 @@ class PhysicsEngine {
       this.stopSimulation(false);
       this.body.emitter.off();
     });
+    this.body.emitter.on('_positionUpdate',  (properties) => this.positionUpdateHandler(properties));
+    this.body.emitter.on('_physicsUpdate',  (properties) => this.physicsUpdateHandler(properties));
     // For identifying which nodes to send to worker thread
     this.body.emitter.on('dragStart',       (properties) => {this.draggingNodes = properties.nodes;});
     this.body.emitter.on('dragEnd',         () => {
@@ -175,6 +179,8 @@ class PhysicsEngine {
    * configure the engine.
    */
   initEmbeddedPhysics() {
+    this.positionUpdateHandler = () => {};
+    this.physicsUpdateHandler = () => {};
     if (this.physicsWorker) {
       this.options.useWorker = false;
       this.physicsWorker.terminate();
@@ -237,10 +243,24 @@ class PhysicsEngine {
         this.physicsWorkerMessageHandler(event);
       });
       this.physicsWorker.onerror = (event) => {
-        console.error('Falling back to embedded physics engine');
+        console.error('Falling back to embedded physics engine', event);
         this.initEmbeddedPhysics();
         // throw new Error(event.message + " (" + event.filename + ":" + event.lineno + ")");
       };
+      this.positionUpdateHandler = (positions) => {
+        this.physicsWorker.postMessage({type: 'updatePositions', data: positions});
+      };
+      this.physicsUpdateHandler = (properties) => {
+        if (properties.options.physics !== undefined) {
+          if (properties.options.physics) {
+            this.physicsWorker.postMessage({type: 'addElements', data: 'TODO: createNode'});
+          } else {
+            this.physicsWorker.postMessage({type: 'removeElements', data: properties.id});
+          }
+        } else {
+          this.physicsWorker.postMessage({type: 'updateProperty', data: properties});
+        }
+      };
     }
   }
 
@@ -259,8 +279,8 @@ class PhysicsEngine {
           let node = this.body.nodes[nodeId];
           // handle case where we get a positions from an old physicsObject
           if (node) {
-            node.x = positions[nodeId].x;
-            node.y = positions[nodeId].y;
+            node.setX(positions[nodeId].x);
+            node.setY(positions[nodeId].y);
           }
         }
         break;
@@ -719,7 +739,7 @@ class PhysicsEngine {
       let ax   = (forces[nodeId].x - dx) / node.options.mass;        // acceleration
       velocities[nodeId].x += ax * timestep;                         // velocity
       velocities[nodeId].x = (Math.abs(velocities[nodeId].x) > maxVelocity) ? ((velocities[nodeId].x > 0) ? maxVelocity : -maxVelocity) : velocities[nodeId].x;
-      node.x   += velocities[nodeId].x * timestep;                    // position
+      node.setX(node.x + velocities[nodeId].x * timestep);           // position
     }
     else {
       forces[nodeId].x = 0;
@@ -731,7 +751,7 @@ class PhysicsEngine {
       let ay   = (forces[nodeId].y - dy) / node.options.mass;         // acceleration
       velocities[nodeId].y += ay * timestep;                          // velocity
       velocities[nodeId].y = (Math.abs(velocities[nodeId].y) > maxVelocity) ? ((velocities[nodeId].y > 0) ? maxVelocity : -maxVelocity) : velocities[nodeId].y;
-      node.y   += velocities[nodeId].y * timestep;                     // position
+      node.setY(node.y + velocities[nodeId].y * timestep);            // position
     }
     else {
       forces[nodeId].y = 0;
diff --git a/lib/network/modules/PhysicsWorker.js b/lib/network/modules/PhysicsWorker.js
index 70994847..197a95ad 100644
--- a/lib/network/modules/PhysicsWorker.js
+++ b/lib/network/modules/PhysicsWorker.js
@@ -9,7 +9,10 @@ import ForceAtlas2BasedCentralGravitySolver from './components/physics/FA2BasedC
 
 class PhysicsWorker {
   constructor(postMessage) {
-    this.body = {};
+    this.body = {
+      nodes: {},
+      edges: {}
+    };
     this.physicsBody = {physicsNodeIndices:[], physicsEdgeIndices:[], forces: {}, velocities: {}};
     this.postMessage = postMessage;
     this.options = {};
@@ -35,28 +38,47 @@ class PhysicsWorker {
         break;
       case 'updatePositions':
         let updatedNode = this.body.nodes[msg.data.id];
-        updatedNode.x = msg.data.x;
-        updatedNode.y = msg.data.y;
-        this.physicsBody.forces[updatedNode.id] = {x: 0, y: 0};
-        this.physicsBody.velocities[updatedNode.id] = {x: 0, y: 0};
+        if (updatedNode) {
+          updatedNode.x = msg.data.x;
+          updatedNode.y = msg.data.y;
+          this.physicsBody.forces[updatedNode.id] = {x: 0, y: 0};
+          this.physicsBody.velocities[updatedNode.id] = {x: 0, y: 0};
+        }
         break;
-      case 'updateFixed':
-        let fixedNode = this.body.nodes[msg.data.id];
-        fixedNode.x = msg.data.x;
-        fixedNode.y = msg.data.y;
-        fixedNode.options.fixed.x = msg.data.fixed.x;
-        fixedNode.options.fixed.y = msg.data.fixed.y;
+      case 'updateProperty':
+        let optionsNode = this.body.nodes[msg.data.id];
+        if (optionsNode) {
+          let opts = msg.data.options;
+          // TODO see if we need a position with fixed
+          if (opts.fixed) {
+            if (opts.fixed.x !== undefined) {
+              optionsNode.options.fixed.x = opts.fixed.x;
+            }
+            if (opts.fixed.y !== undefined) {
+              optionsNode.options.fixed.y = opts.fixed.y;
+            }
+          }
+          if (opts.mass !== undefined) {
+            optionsNode.options.mass = opts.mass;
+          }
+        }
         break;
-      case 'options':
-        this.options = msg.data;
-        this.timestep = this.options.timestep;
-        this.init();
+      case 'addElements':
+        console.log('add');
+        break;
+      case 'removeElements':
+        console.log('remove');
         break;
       case 'physicsObjects':
         this.body.nodes = msg.data.nodes;
         this.body.edges = msg.data.edges;
         this.updatePhysicsData();
         break;
+      case 'options':
+        this.options = msg.data;
+        this.timestep = this.options.timestep;
+        this.init();
+        break;
       default:
         console.warn('unknown message from PhysicsEngine', msg);
     }
diff --git a/lib/network/modules/components/Node.js b/lib/network/modules/components/Node.js
index 89152195..9e88e744 100644
--- a/lib/network/modules/components/Node.js
+++ b/lib/network/modules/components/Node.js
@@ -59,8 +59,8 @@ class Node {
     this.grouplist = grouplist;
 
     // state options
-    this.x = undefined;
-    this.y = undefined;
+    this._x = undefined;
+    this._y = undefined;
     this.baseSize = this.options.size;
     this.baseFontSize = this.options.font.size;
     this.predefinedPosition = false; // used to check if initial fit should just take the range or approximate
@@ -71,6 +71,39 @@ class Node {
     this.setOptions(options);
   }
 
+  get x() {
+    return this._x;
+  }
+
+  set x(newX) {
+    this._x = newX;
+    this.body.emitter.emit('_positionUpdate', {id: this.id, x: this._x, y: this._y});
+  }
+
+  /**
+   * Non emitting version for use by physics engine so we don't create infinite loops.
+   * @param newX
+   */
+  setX(newX) {
+    this._x = newX;
+  }
+
+  get y() {
+    return this._y;
+  }
+
+  set y(newY) {
+    this._y = newY;
+    this.body.emitter.emit('_positionUpdate', {id: this.id, x: this._x, y: this._y});
+  }
+
+  /**
+   * Non emitting version for use by physics engine so we don't create infinite loops.
+   * @param newY
+   */
+  setY(newY) {
+    this._y = newY;
+  }
 
   /**
    * Attach a edge to the node
@@ -136,7 +169,7 @@ class Node {
     }
 
     // this transforms all shorthands into fully defined options
-    Node.parseOptions(this.options, options, true, this.globalOptions);
+    this.parseOptions(this.options, options, true, this.globalOptions);
 
     // load the images
     if (this.options.image !== undefined) {
@@ -151,8 +184,16 @@ class Node {
     this.updateLabelModule();
     this.updateShape(currentShape);
 
+    if (options.mass !== undefined) {
+      this.options.mass = options.mass;
+      this.body.emitter.emit('_physicsUpdate', {id: this.id, options: {mass: options.mass}});
+    }
+    if (options.physics !== undefined) {
+      this.options.physics = options.physics;
+      this.body.emitter.emit('_physicsUpdate', {id: this.id, options: {physics: options.physics}});
+    }
 
-    if (options.hidden !== undefined || options.physics !== undefined) {
+    if (options.hidden !== undefined) {
       return true;
     }
     return false;
@@ -165,7 +206,7 @@ class Node {
    * @param parentOptions
    * @param newOptions
    */
-  static parseOptions(parentOptions, newOptions, allowDeletion = false, globalOptions = {}) {
+  parseOptions(parentOptions, newOptions, allowDeletion = false, globalOptions = {}) {
     var fields = [
       'color',
       'font',
@@ -189,15 +230,26 @@ class Node {
     // handle the fixed options
     if (newOptions.fixed !== undefined && newOptions.fixed !== null) {
       if (typeof newOptions.fixed === 'boolean') {
-        parentOptions.fixed.x = newOptions.fixed;
-        parentOptions.fixed.y = newOptions.fixed;
+        if (parentOptions.fixed.x !== newOptions.fixed || parentOptions.fixed.y !== newOptions.fixed) {
+          parentOptions.fixed.x = newOptions.fixed;
+          parentOptions.fixed.y = newOptions.fixed;
+          this.body.emitter.emit('_physicsUpdate', {id: this.id, options: {fixed: {x: newOptions.fixed, y: newOptions.fixed}}});
+        }
       }
       else {
-        if (newOptions.fixed.x !== undefined && typeof newOptions.fixed.x === 'boolean') {
+        if (newOptions.fixed.x !== undefined &&
+            typeof newOptions.fixed.x === 'boolean' &&
+            parentOptions.fixed.x !== newOptions.fixed.x)
+        {
           parentOptions.fixed.x = newOptions.fixed.x;
+          this.body.emitter.emit('_physicsUpdate', {id: this.id, options: {fixed: {x: newOptions.fixed.x}}});
         }
-        if (newOptions.fixed.y !== undefined && typeof newOptions.fixed.y === 'boolean') {
+        if (newOptions.fixed.y !== undefined &&
+            typeof newOptions.fixed.y === 'boolean' &&
+            parentOptions.fixed.y !== newOptions.fixed.y)
+        {
           parentOptions.fixed.y = newOptions.fixed.y;
+          this.body.emitter.emit('_physicsUpdate', {id: this.id, options: {fixed: {y: newOptions.fixed.y}}});
         }
       }
     }