diff --git a/src/Participants/ParticipantUDP.cs b/src/Participants/ParticipantUDP.cs
index 2dced60..5e668e8 100644
--- a/src/Participants/ParticipantUDP.cs
+++ b/src/Participants/ParticipantUDP.cs
@@ -7,40 +7,41 @@ using System.Net.NetworkInformation;
 namespace RoboidControl {
 
     /// <summary>
-    /// A participant is used for communcation between things
+    /// A participant using UDP communication
     /// </summary>
+    /// A local participant is the local device which can communicate with
+    /// other participants It manages all local things and communcation with other
+    /// participants. Each application has a local participant which is usually
+    /// explicit in the code. An participant can be isolated. In that case it is
+    /// standalong and does not communicate with other participants.
+    ///
+    /// It is possible to work with an hidden participant by creating things without
+    /// specifying a participant in the constructor. In that case an hidden isolated
+    /// participant is created which can be obtained using
+    /// RoboidControl::IsolatedParticipant::Isolated().
+    /// @sa RoboidControl::Thing::Thing()
     public class ParticipantUDP : Participant {
-        public byte[] buffer = new byte[1024];
-        public ulong publishInterval = 3000; // = 3 seconds
-
-        public string name = "Participant";
-
-        public bool isIsolated = false;
-        public Participant remoteSite;
-
-        public IPEndPoint endPoint = null;
-        public UdpClient udpClient = null;
-        public string broadcastIpAddress = "255.255.255.255";
-
-        public readonly ConcurrentQueue<IMessage> messageQueue = new ConcurrentQueue<IMessage>();
 
         #region Init
 
         /// <summary>
-        /// Create a participant with the give UDP port
+        /// Create a participant without connecting to a site
         /// </summary>
         /// <param name="port">The port number on which to communicate</param>
+        /// These participant typically broadcast Participant messages to let site
+        /// servers on the local network know their presence. Alternatively they can
+        /// broadcast information which can be used directly by other participants.
         public ParticipantUDP(int port = 0) : base("127.0.0.1", port) {
             if (this.port == 0)
                 this.isIsolated = true;
             Participant.AddParticipant(this);
         }
-
         /// <summary>
-        /// Create a new participant for a site at the given address and port
+        ///  Create a participant which will try to connect to a site.
         /// </summary>
         /// <param name="ipAddress">The ip address of the site server</param>
         /// <param name="port">The port number of the site server</param>
+        /// <param name="localPort">The port used by the local participant</param>
         public ParticipantUDP(string ipAddress, int port = 7681, int localPort = 7681) : base("127.0.0.1", localPort) {
             if (this.port == 0)
                 this.isIsolated = true;
@@ -81,16 +82,48 @@ namespace RoboidControl {
 
         }
 
+        private static ParticipantUDP isolatedParticipant = null;
+
         /// <summary>
-        /// Create a participant using the given udp client
+        /// Isolated participant is used when the application is run without networking
         /// </summary>
-        /// <param name="udpClient">UDP client to use for communication</param>
-        /// <param name="port">The port number on which to communicate</param>
-        public ParticipantUDP(UdpClient udpClient, int port) : this() {
-            this.udpClient = udpClient;
-            this.port = port;
+        /// <returns>A participant without networking support</returns>
+        public static ParticipantUDP Isolated() {
+            if (isolatedParticipant == null)
+                isolatedParticipant = new ParticipantUDP(0);
+            return isolatedParticipant;
         }
 
+        #endregion Init
+
+        /// <summary>
+        /// The name of the participant
+        /// </summary>
+        public string name = "ParticipantUDP";
+
+        /// <summary>
+        /// True if the participant is running isolated.
+        /// </summary>
+        /// Isolated participants do not communicate with other participants
+        public bool isIsolated = false;
+        /// <summary>
+        /// The remote site when this participant is connected to a site
+        /// </summary>
+        public Participant remoteSite = null;
+
+        /// <summary>
+        /// The interval in milliseconds for publishing (broadcasting) data on the local network
+        /// </summary>
+        public ulong publishInterval = 3000; // = 3 seconds
+
+        public byte[] buffer = new byte[1024];
+
+        public IPEndPoint endPoint = null;
+        public UdpClient udpClient = null;
+        public string broadcastIpAddress = "255.255.255.255";
+
+        public readonly ConcurrentQueue<IMessage> messageQueue = new ConcurrentQueue<IMessage>();
+
         protected void GetBroadcastAddress(IPAddress ip, IPAddress subnetMask) {
             byte[] ipBytes = ip.GetAddressBytes();
             byte[] maskBytes = subnetMask.GetAddressBytes();
@@ -110,14 +143,6 @@ namespace RoboidControl {
             Console.WriteLine($"Broadcast address: {this.broadcastIpAddress}");
         }
 
-        private static ParticipantUDP isolatedParticipant = null;
-        public static ParticipantUDP Isolated() {
-            if (isolatedParticipant == null)
-                isolatedParticipant = new ParticipantUDP(0);
-            return isolatedParticipant;
-        }
-        #endregion Init
-
         #region Update
 
         protected ulong nextPublishMe = 0;
@@ -208,9 +233,19 @@ namespace RoboidControl {
             this.Send(owner, new ThingMsg(this.networkId, thing));
             this.Send(owner, new NameMsg(this.networkId, thing));
             this.Send(owner, new ModelUrlMsg(this.networkId, thing));
+            this.Send(owner, new PoseMsg(this.networkId, thing));
             this.Send(owner, new BinaryMsg(this.networkId, thing));
         }
 
+        public void PublishThingInfo(Thing thing) {
+            // Console.WriteLine("Publish thing info");
+            this.Publish(new ThingMsg(this.networkId, thing));
+            this.Publish(new NameMsg(this.networkId, thing));
+            this.Publish(new ModelUrlMsg(this.networkId, thing));
+            this.Publish(new PoseMsg(this.networkId, thing));
+            this.Publish(new BinaryMsg(this.networkId, thing));
+        }
+
         public bool Send(Participant owner, IMessage msg) {
             int bufferSize = msg.Serialize(ref this.buffer);
             if (bufferSize <= 0)
@@ -222,14 +257,6 @@ namespace RoboidControl {
             return true;
         }
 
-        public void PublishThingInfo(Thing thing) {
-            // Console.WriteLine("Publish thing info");
-            this.Publish(new ThingMsg(this.networkId, thing));
-            this.Publish(new NameMsg(this.networkId, thing));
-            this.Publish(new ModelUrlMsg(this.networkId, thing));
-            this.Publish(new BinaryMsg(this.networkId, thing));
-        }
-
         public bool Publish(IMessage msg) {
             int bufferSize = msg.Serialize(ref this.buffer);
             if (bufferSize <= 0)
@@ -240,24 +267,6 @@ namespace RoboidControl {
             return true;
         }
 
-        // public bool SendBuffer(int bufferSize) {
-        //     //if (this.ipAddress == null)
-        //     //    return false;
-
-        //     // UnityEngine.Debug.Log($"Send msg {buffer[0]} to {ipAddress}");
-        //     //this.udpClient.Send(this.buffer, bufferSize, this.ipAddress, this.port);
-        //     this.udpClient?.Send(this.buffer, bufferSize, this.endPoint);
-        //     return true;
-        // }
-
-        // public bool PublishBuffer(int bufferSize) {
-        //     if (this.broadcastIpAddress == null)
-        //         return false;
-
-        //     this.udpClient?.Send(this.buffer, bufferSize, this.broadcastIpAddress, this.port);
-        //     return true;
-        // }
-
         #endregion
 
         #region Receive
@@ -350,19 +359,19 @@ namespace RoboidControl {
 
         protected virtual void Process(Participant sender, InvestigateMsg msg) {
 #if DEBUG
-            Console.WriteLine($"Participant: InvestigateMsg [{msg.networkId}/{msg.thingId}]");
+            Console.WriteLine($"{this.name}: Process InvestigateMsg [{msg.networkId}/{msg.thingId}]");
 #endif
         }
 
         protected virtual void Process(Participant sender, ThingMsg msg) {
 #if DEBUG            
-            Console.WriteLine($"Participant: Process ThingMsg [{msg.networkId}/{msg.thingId}] {msg.thingType} {msg.parentId}");
+            Console.WriteLine($"{this.name}: Process ThingMsg [{msg.networkId}/{msg.thingId}] {msg.thingType} {msg.parentId}");
 #endif            
         }
 
         protected virtual void Process(Participant sender, NameMsg msg) {
 #if DEBUG            
-            Console.WriteLine($"Participant: Process NameMsg [{msg.networkId}/{msg.thingId}] {msg.nameLength} {msg.name}");
+            Console.WriteLine($"{this.name}: Process NameMsg [{msg.networkId}/{msg.thingId}] {msg.nameLength} {msg.name}");
 #endif
 
             Thing thing = sender.Get(msg.thingId);
@@ -372,7 +381,7 @@ namespace RoboidControl {
 
         protected virtual void Process(Participant sender, ModelUrlMsg msg) {
 #if DEBUG            
-            Console.WriteLine($"Participant: Process ModelUrlMsg [{msg.networkId}/{msg.thingId}] {msg.urlLength} {msg.url}");
+            Console.WriteLine($"{this.name}: Process ModelUrlMsg [{msg.networkId}/{msg.thingId}] {msg.urlLength} {msg.url}");
 #endif
 
             Thing thing = sender.Get(msg.thingId);
@@ -382,28 +391,29 @@ namespace RoboidControl {
 
         protected virtual void Process(Participant sender, PoseMsg msg) {
 #if DEBUG            
-            Console.WriteLine($"Participant: Process PoseMsg [{msg.networkId}/{msg.thingId}] {msg.poseType}");
+            Console.WriteLine($"{this.name}: Process PoseMsg [{msg.networkId}/{msg.thingId}] {msg.poseType}");
 #endif            
-            Thing thing = sender.Get(msg.thingId);
-            if (thing != null) {
-                if ((msg.poseType & PoseMsg.Pose_Position) != 0)
-                    thing.position = msg.position;
-                if ((msg.poseType & PoseMsg.Pose_Orientation) != 0)
-                    thing.orientation = msg.orientation;
-                if ((msg.poseType & PoseMsg.Pose_LinearVelocity) != 0) {
-                    thing.linearVelocity = msg.linearVelocity;
-                    //Console.Write($"linear velocity = {thing.linearVelocity.ToVector3()}");
-                }
-                if ((msg.poseType & PoseMsg.Pose_AngularVelocity) != 0) {
-                    thing.angularVelocity = msg.angularVelocity;
-                    //Console.Write($"angular velocity = {thing.angularVelocity.ToVector3()}");
-                }
-            }
+            Participant owner = Participant.GetParticipant(msg.networkId);
+            if (owner == null)
+                return;
+
+            Thing thing = owner.Get(msg.thingId);
+            if (thing == null)
+                return;
+
+            if ((msg.poseType & PoseMsg.Pose_Position) != 0)
+                thing.position = msg.position;
+            if ((msg.poseType & PoseMsg.Pose_Orientation) != 0)
+                thing.orientation = msg.orientation;
+            if ((msg.poseType & PoseMsg.Pose_LinearVelocity) != 0)
+                thing.linearVelocity = msg.linearVelocity;
+            if ((msg.poseType & PoseMsg.Pose_AngularVelocity) != 0)
+                thing.angularVelocity = msg.angularVelocity;
         }
 
         protected virtual void Process(Participant sender, BinaryMsg msg) {
 #if DEBUG
-            Console.WriteLine($"Participant: Process BinaryMsg [{msg.networkId}/{msg.thingId}] {msg.dataLength}");
+            Console.WriteLine($"{this.name}: Process BinaryMsg [{msg.networkId}/{msg.thingId}] {msg.dataLength}");
 #endif
             Thing thing = sender.Get(msg.thingId);
             thing?.ProcessBinary(msg.data);
diff --git a/src/Participants/SiteServer.cs b/src/Participants/SiteServer.cs
index fc3d2d9..ab79190 100644
--- a/src/Participants/SiteServer.cs
+++ b/src/Participants/SiteServer.cs
@@ -10,10 +10,12 @@ namespace RoboidControl {
     /// </summary>
     public class SiteServer : ParticipantUDP {
 
+        #region Init
+
         /// <summary>
         /// Create a new site server
         /// </summary>
-        /// <param name="port"></param>
+        /// <param name="port">The port of which to receive the messages</param>
         public SiteServer(int port = 7681) : base(port) {
             this.name = "Site Server";
             Participant.AddParticipant(this);
@@ -51,6 +53,8 @@ namespace RoboidControl {
 
         }
 
+        #endregion Init
+
         /// <summary>
         ///  Close the site
         /// </summary>