Merge branch 'master' of https://github.com/ifcquery/ifcplusplus

Author: ifcquery

README.md

@@ -1,13 +1,57 @@
 ABOUT IFC++
 =============
-## Summary
-IFC++ is an open source IFC implementation for C++. It was originally developed at the Bauhaus University Weimar.
 
+IFC++ is an open source IFC implementation for C++.
+It is very fast, but it has not the lowest possible memory footprint, because it has a complete class model.
+
+
+
+Benefits of the complete class model are (among others):
+- you can easily instantiate objects and access member variables, for example:
+```cpp
+  shared_ptr<IfcCartesianPoint> ifcPoint = make_shared<IfcCartesianPoint>();
+  shared_ptr<IfcPolyLoop> polyLoop = make_shared<IfcPolyLoop>()
+  polyLoop->m_Polygon.push_back(ifcPoint);
+```
+
+- you can navigate the model easily by accessing member variables directly, including inverse attributes:
+```cpp
+shared_ptr<IfcBuildingStorey> currentBuildingStorey = ...;
+for (auto it : currentBuildingStorey->m_IsDecomposedBy_inverse)
+{
+   shared_ptr<IfcRelAggregates> relAggregates(it);
+
+   for (auto it2 : relAggregates->m_RelatedObjects)
+   {
+      shared_ptr<IfcObjectDefinition> child_obj = (it2);
+      shared_ptr<IfcWallStandardCase> wall = dynamic_pointer_cast<IfcWallStandardCase>(child_obj);
+      if(wall)
+      {
+         // do something with wall
+      }
+    }
+ }
+```
+  Inverse attribute pointers are automatically generated by IFC++ for all object references in the model.
+  
+- casting is possible for all types:
+ ```cpp
+  shared_ptr<IfcPropertySet> pset = dynamic_pointer_cast<IfcPropertySet>(relatingPropertyDefinition);
+  ```
+
+- Professional support is available for bug fixing or custom implementations on www.ifcquery.com.
+
+
+ 
+
+  
 ## License
 The project is published under the MIT license, which means that you can use it for any purpose, personal or commercial. There is no obligation to publish your source code.
 
+
 ## Details and download of executable
-Additional information as well as download links to the viewer application is on this project website: http://www.ifcquery.com
+Open source example application for Qt here available: https://github.com/ifcquery/ifcplusplus/releases
+
 
 ## How to build the library and example application on Windows and Linux
 https://github.com/ifcquery/ifcplusplus/wiki/Build-instructions