The idea of the "Virtual Aachen Project" was to create a virtual version of the city of Aachen during a practical course held in 2008 at the computer graphics group at RWTH Aachen. The same was previously tried by a group of architects who were only able to reproduce a small fracture of the city by hand.

During the course, groups of 2-3 students focused on the different parts, like reproducing the city layout from city maps, gathering textures, creating hires models of highly recognizable city buildings or bringing it all together in the final rendering to create a virtual walk-through of the city of Aachen. I've been part of the rendering group, where we need to visualize the large amounts of resulting geometry and texture data provided by the other groups in real-time using our own OpenGL-based 3D graphics engine. This is a screen shot of the final result, including a dynamic sky sphere:

The City Model

The 3D model of Aachen was generated using highly detailed city maps provided by the land registry office ("Katasteramt") of Aachen:

Models of Landmark Buildings

Special models were created during the project to leverage the recognition of certain landmark buildings like the "Aachener Dom" or the "Ponttor":

 

 

 

 

 

View-dependent texturing

Some Buildings were textured using images taken from different view positions to allow shader-based view dependent texturing. Have a look at the windows and the sign of the building:

 

 

 

 

 

 

 

 Implementation

The implementation was done in C++, using our own octree implementation for handling the geometry data, as well as OpenGL for the rendering and Qt to design the GUI:

For more information, please have a look at our presentation slides.