Change parameters of the scenes due to changes in the calculations of the Image Tracker. Add initialization flags.

demos/hello-aframe/index.html

             <ar-root reference-image="mage">
 
                 <!-- Switch from top view to front view -->
-                <a-entity rotation="-90 0 0" position="0 -0.5 0">
+                <a-entity rotation="-90 0 0" position="0 -0.8 0">
 
                     <!-- Light -->
                     <a-light type="ambient" intensity="1.5"></a-light>
 
             <!-- The cat -->
             <ar-root reference-image="cat">
-                <a-entity rotation="-90 0 0" position="0 -0.5 0">
+                <a-entity rotation="-90 0 0" position="0 -0.8 0">
                     <a-light type="ambient" intensity="1.5"></a-light>
 
                     <a-entity

demos/hello-aframe/video.html

             <ar-root reference-image="mage">
 
                 <!-- Switch from top view to front view -->
-                <a-entity rotation="-90 0 0" position="0 -0.5 0">
+                <a-entity rotation="-90 0 0" position="0 -0.8 0">
 
                     <!-- Light -->
                     <a-light type="ambient" intensity="1.5"></a-light>
 
             <!-- The cat -->
             <ar-root reference-image="cat">
-                <a-entity rotation="-90 0 0" position="0 -0.5 0">
+                <a-entity rotation="-90 0 0" position="0 -0.8 0">
                     <a-light type="ambient" intensity="1.5"></a-light>
 
                     <a-entity

demos/hello-babylon/demo.js

         super();
 
         this._objects = { };
+        this._initialized = false;
     }
 
     /**
         });
 
         // Change the point of view - slightly
-        ar.root.position.y = -0.5;
+        ar.root.position.y = -0.8;
 
         // Initialize objects
         this._initLight(ar);
             this._initMage(ar),
             this._initCat(ar),
         ]);
+
+        // done!
+        this._initialized = true;
     }
 
     /**
 
     _initLight(ar)
     {
-        const light = new BABYLON.HemisphericLight('light', BABYLON.Vector3.Down());
+        const light = new BABYLON.HemisphericLight('light', BABYLON.Vector3.Up());
         light.intensity = 1.0;
         light.diffuse.set(1, 1, 0.9);
         light.specular.set(0, 0, 0);
 
     _onTargetFound(referenceImage)
     {
+        // make sure that the scene is initialized
+        if(!this._initialized) {
+            alert(`Target \"${referenceImage.name}\" was found, but the 3D scene is not yet initialized!`);
+            return;
+        }
+
         // change the scene based on the tracked image
         switch(referenceImage.name) {
             case 'mage':

demos/hello-three/demo.js

         super();
 
         this._objects = { };
+        this._initialized = false;
     }
 
     /**
         // ar.root, a node that is automatically aligned to the physical scene.
         // Adjusting ar.root will adjust all virtual objects.
         Utils.switchToFrontView(ar);
-        ar.root.position.set(0, -0.5, 0);
+        ar.root.position.set(0, -0.8, 0);
 
-        // initialize objects
+        // Initialize objects
         this._initLight(ar);
         this._initText(ar);
         this._initMagicCircle(ar);
             this._initMage(ar),
             this._initCat(ar),
         ]);
+
+        // done!
+        this._initialized = true;
     }
 
     /**
 
     _onTargetFound(referenceImage)
     {
+        // make sure that the scene is initialized
+        if(!this._initialized) {
+            alert(`Target \"${referenceImage.name}\" was found, but the 3D scene is not yet initialized!`);
+            return;
+        }
+
         // change the scene based on the tracked image
         switch(referenceImage.name) {
             case 'mage':