Typo and package name buildingphysics has to be lower case

de.hftstuttgart.buildingphysics/model/buildingphysics.ecore

 <?xml version="1.0" encoding="UTF-8"?>
 <ecore:EPackage xmi:version="2.0" xmlns:xmi="http://www.omg.org/XMI" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xmlns:ecore="http://www.eclipse.org/emf/2002/Ecore" name="BuildingBhysics" nsURI="http://www.example.org/buildingphysics"
+    xmlns:ecore="http://www.eclipse.org/emf/2002/Ecore" name="buildingphysics" nsURI="http://www.example.org/buildingphysics"
     nsPrefix="BuildingPhysics">
   <eClassifiers xsi:type="ecore:EClass" name="BuildingPhysicsCatalog">
     <eStructuralFeatures xsi:type="ecore:EAttribute" name="author" lowerBound="1"