This year, the Computer Graphics Group has scored three papers at the Eurographics Conference which is the leading Computer Graphics conference in Europe. All three papers are loosely related to the topic of 3D city reconstruction but each addressing quite different aspects with very different methodological approaches.
The paper "Rationalization of Triangle-Based Point-Folding Structures" proposes an automatic algorithm for the rationalization of folded light- weight structures in architecture. Such structures are usually made from a large number of individual panels. Our algorithm minimizes the number of *different* panels such that the overall building costs can be reduced significantly by maximizing the re-use of panels.
For more standardized building architectures, we are developing an interactive 3D modeling tool that allows even untrained users to generate digital replicas of real houses. This is achieved by associating constraints like parallelism, orthogonality, or verticality with the models in order to constrain the potential design space to "architecturally reasonable" structures. In the paper "Linear Analysis of Nonlinear Constraints for Interactive Geometric Modeling" a new mathematical technique is derived which finds the minimum set of constraints that have to be violated in order to accommodate a shape modification requested by the user.
Finally in the paper "Procedural Interpolation of Historical City Maps" we go from 3D cities to 4D cities by generating animations that show the urban development over decades and centuries. The input to our system consists of a number of historical city maps and possibly some other historical data. The output is a temporal sequence of construction and destruction events for the individual buildings in the city.
See the publications page on http://www.graphics.rwth-aachen.de for more details and demo videos.