diff --git a/src/de/tud/kom/p2psim/impl/topology/component/AbstractTopologyComponent.java b/src/de/tud/kom/p2psim/impl/topology/component/AbstractTopologyComponent.java
index 670d0e6e089c7969fc902ba94e3041a67c3972d6..67b4ac0060f13f748d95bf05c863282982cb9a51 100644
--- a/src/de/tud/kom/p2psim/impl/topology/component/AbstractTopologyComponent.java
+++ b/src/de/tud/kom/p2psim/impl/topology/component/AbstractTopologyComponent.java
@@ -25,7 +25,6 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-
 import de.tud.kom.p2psim.api.common.SimHost;
 import de.tud.kom.p2psim.api.linklayer.mac.PhyType;
 import de.tud.kom.p2psim.api.topology.Topology;
@@ -100,11 +99,9 @@ public abstract class AbstractTopologyComponent implements TopologyComponent {
 		topology.addComponent(this);
 		movementModel.placeComponent(this);
 
-		if (placementModel != null) {
-			/*
-			 * Legacy support for placement models.
-			 */
-			position.set(placementModel.place(this));
+		if (placementModel != null) {			
+			// retrieve the initial position of this topology component 
+			position.set(placementModel.place(this));		
 		}
 
 		if (registerAsInformationProviderInSiS) {
diff --git a/src/de/tud/kom/p2psim/impl/topology/placement/GridPositionDistribution.java b/src/de/tud/kom/p2psim/impl/topology/placement/GridPositionDistribution.java
index 50e77ed217240e10da84e81b306544cf27ae9b1b..82c04cc997eabdd4d151df51cb42ff148e3dcf48 100644
--- a/src/de/tud/kom/p2psim/impl/topology/placement/GridPositionDistribution.java
+++ b/src/de/tud/kom/p2psim/impl/topology/placement/GridPositionDistribution.java
@@ -69,9 +69,9 @@ public class GridPositionDistribution implements PlacementModel {
 	@Override
 	public PositionVector place(TopologyComponent comp) {
 		if (positions.isEmpty()) {
-			calcPositions2D();
+			calcPositions3D();
 		}
-		PositionVector pos = positions.get(placedComponents);
+		PositionVector pos = positions.get(placedComponents);		
 		placedComponents = (placedComponents + 1) % numberOfComponents;
 		return pos;
 	}
@@ -83,8 +83,8 @@ public class GridPositionDistribution implements PlacementModel {
 	public void setFakeNumberOfComponents(int fakeNumberOfComponents) {
 		this.fakeNumberOfComponents = fakeNumberOfComponents;
 	}
-
-	private void calcPositions2D() {
+	
+	private void calcPositions3D() {
 		if (fakeNumberOfComponents != -1) {
 			numberOfComponents = fakeNumberOfComponents;
 		}
@@ -104,7 +104,7 @@ public class GridPositionDistribution implements PlacementModel {
 					ycenter += random.nextDouble() * dist_y / 2
 							- dist_y / 4;
 				}
-				PositionVector vec = new PositionVector(xcenter, ycenter);
+				PositionVector vec = new PositionVector(xcenter, ycenter, 0);
 				positions.add(vec);
 			}
 		}
diff --git a/src/de/tud/kom/p2psim/impl/topology/util/PositionVector.java b/src/de/tud/kom/p2psim/impl/topology/util/PositionVector.java
index b0a07064e1a739c589434b5caccb128470bc9a30..8c15b2e2b92e84c1b3b35916213472ce425c5c56 100644
--- a/src/de/tud/kom/p2psim/impl/topology/util/PositionVector.java
+++ b/src/de/tud/kom/p2psim/impl/topology/util/PositionVector.java
@@ -49,8 +49,11 @@ import de.tudarmstadt.maki.simonstrator.api.component.sensor.location.Location;
  * - 05.09.2018 Julian Zobel: Added location support for third dimension (altitude)
  * and removed a bug in the moveStep() function.
  * 
+ * - 10.09.2018 Julian Zobel: Adapted the replace function to work properly without 
+ * assertions. Replace does now fully replace the position vector entries.
+ * 
  * @author Bjoern Richerzhagen, Julian Zobel
- * @version 1.1, 06.09.2018
+ * @version 1.2, 10.09.2018
  */
 public class PositionVector implements Location {
 
@@ -141,21 +144,30 @@ public class PositionVector implements Location {
 	
 	
 	/*
-	 * 
+	 *  
 	 * 
 	 */
 	@Override
 	public void setLatitudeOrY(double latitudeOrY)
-			throws UnsupportedOperationException {
+	{
 		this.setEntry(1, latitudeOrY);
 	}
 	
 	@Override
 	public void setLongitudeOrX(double longitudeOrX)
-			throws UnsupportedOperationException {
+	{
 		this.setEntry(0, longitudeOrX);
 	}
 	
+	@Override
+	public void setAltitude(double altitude) {
+		if(hasAltitude()) {		
+			this.setEntry(2, altitude);
+		}	
+		else 
+			throw new AssertionError("Setting altitude only possible with three dimensional PositionVector");
+	}
+	
 	@Override
 	public void setAccuracy(double accuracy)
 			throws UnsupportedOperationException {
@@ -376,7 +388,7 @@ public class PositionVector implements Location {
 
 	@Override
 	public String toString() {				
-		return "PV " + Arrays.toString(values) + "";			
+		return "PV("+getDimensions()+") " + Arrays.toString(values) + "";			
 	}
 	
 	@Override
@@ -435,8 +447,11 @@ public class PositionVector implements Location {
 	 * @param vector
 	 */
 	public void replace(PositionVector vector) {
-		assert dimensions == vector.getDimensions();
-		this.values = Arrays.copyOf(vector.values, dimensions);
+		this.dimensions = vector.getDimensions();
+		this.values = new double[dimensions];
+		for (int i = 0; i < this.dimensions; i++) {
+			setEntry(i, vector.getEntry(i));
+		}
 	}
 
 	/**
@@ -457,6 +472,7 @@ public class PositionVector implements Location {
 	 * @param speed
 	 * @return
 	 */
+	@Deprecated
 	public PositionVector moveStep(PositionVector destination, double speed) {
 
 		if(speed == 0) {
@@ -492,8 +508,12 @@ public class PositionVector implements Location {
 
 	@Override
 	public void set(Location l) {
-		assert (l instanceof PositionVector);
-		this.replace((PositionVector) l);
+		if (l instanceof PositionVector) {
+			this.replace((PositionVector) l);
+		}
+		else {
+			throw new AssertionError("Cannot replace PositionVector with Location");
+		}
 	}
 
 	@Override