PATHS – Pathlet Animation Tool for Hydrogeological Simulations

Imagination and intuition are challenged when modeling water systems, especially regarding subsurface flow phenomena. This is due to the fact that the occurring processes elude direct observability. For example, the system setup can only be developed with the help of a hydrogeological model based on point source information (bore holes, exploration points). The complexity of the problem is further increased by the use of an integrated approach for the complete water system including surface as well as subsurface components.

Simulation results often have to be presented in a comprehensible way not only in front of an audience consisting of specialists (consultants, public authorities) but also in front of decision makers outside this subject area (stakeholders, general public). The main issues of previous visualization approaches are cluttering, occlusion, and depth perception leading to a loss of their illustrative character.

Goal: Visualization Tool for Intuitive 3D

Main aim of this project has been the development of an intuitive visualization tool for transient 3D flow with the help of pathlets representing short parts of pathlines. They enable the observer to easily capture, understand, and interpret the flow velocity field, especially in the transient case.

Apart from the visualization of water system data for demonstration purposes the project focused on interactive data exploration and analysis for developers of simulation models as well as software. Thereby, the specific requirements regarding the visualization of groundwater and general water system have been accounted for.


Software STRING

During a previous joint project, experience in intuitive visualization of 2D water system flow was gained. This type of 2D flow visualization has proven advantageous concerning its intuitive character. Despite its success, not all 3D flow features could be illustrated and detected with this approach due to the 2D image. Hence, the extension of this concept to 3D was necessary, maintaining the intuitive character.

The following challenges result from the project objective:

  • enhancement of the visual clarity of the pathlet visualization and the depth perception
  • development of specific filtering algorithms for intelligent data handling
  • enabling interactivity on already existing hardware

The project results are implemented in the software STRING. The visualization is based on basic ideas from the field of Grid-free Methods. In particular, the seeding strategy and the movement of the pathlets, which are directly derived from the methodology used there, are to be mentioned here.


Type of Project: ZIM-KF Project
Project Partner: delta h Ingenieurgesellschaft mbH

3D pathlet animation of the Rayleigh Taylor instability combined with the visualization of concentrations by volume rendering.

Influence of a flood wave on the catchment area of an aquifer based on a SPRING transport computation with inverted flow.