Procedural modeling: A new approach to multi-scale design in infrastructure projects

For the planning of large infrastructure projects, such as tunnelled inner-city carriageways, completely different scales have to be considered - ranging from the scale of several kilometres for the general routing of the carriageway down to centimetre scale for the detailed planning of individual track nodes. However, today's planning software hardly supports multiscale approaches to geometric design. The paper presents a new methodology for creating and storing multi-scale geometric models for infrastructure projects which explicitly defines dependencies between the individual levels-of-detail (LoD). These explicit dependencies allow for an automated consistency preservation in case of design changes. The introduced methodology relies on parametric modelling technologies, including the use of dimensional and geometric constraints for defining flexible 2D sketches, as well as the procedural definition of complex 3D models through the sequential use of geometric operations such as extrusion, transformation and Boolean operations. Applying the methodology presented in this paper ensures that modifications on coarse LoDs are automatically propagated to all finer LoDs, thus immediately re-constituting a consistent state of the multi-scale model, as a consequence, significantly reducing the effort required for re-elaboration.