High-resolution geodynamic simulations produce rich three-dimensional data, but that detail can make the results difficult to share. A model may generate many gigabytes of output across thousands of MPI ranks. Loading that data in a browser can take too long, and the files may be too large for a responsive interactive experience.

As part of the Integrated Earth project, we have been building tools and workflows to make these simulations easier to explore online. The work has two connected parts: preparing simulation output at a size and format suited to interactive viewing, and presenting the resulting models and animations in a browser.

Preparing simulation output for the web

Resampling data to a lower resolution is essential for interactive visualization. Smaller files take less time to transfer and parse, and require less memory in the browser. The challenge is to reduce the data while preserving the features that make the model useful to inspect.

ParaView includes resampling filters, but the workflow becomes difficult for spherical data and data with topography. ASPECT can write reference-frame output together with a deformation field; ParaView can then use that information when resampling. To make this process more practical, ASPECT has also been extended to write an intermediate format that can be processed by the project’s viz-tools utilities. The tools resample the data to structured, lower-resolution output, including for spherical models.

In ASPECT, the visualization postprocessor can write the mesh in its undeformed reference configuration along with the mesh displacement and velocity. The displacement describes how the mesh has moved from that reference configuration, allowing ParaView to account for the deformed surface while resampling. For example, this configuration requests those fields in gnuplot output:

subsection Postprocess
  set List of postprocessors = visualization

  subsection Visualization
    set Output undeformed mesh = true
    set Output mesh displacement = true
  end
end

This gives us a route from large simulation output to datasets that are more manageable for interactive rendering, without requiring every browser visitor to load the full-resolution model.

Interactive Starting Earth models

One example of the scale involved is the visualization of one of the Starting Earth models and its input data developed for this project. These simulations can produce around 10 GB of VTK output and use thousands of MPI ranks. We have made interactive versions available in the starting Earth models, so visitors can easily inspect the model in a browser.

The visualization gallery brings together models and animations developed during the project. It provides a place to browse results from different simulations and see how the model fields evolve over time.

The gallery uses a browser-based vtk.js scene viewer, available in the viz-tools repository. The viewer was developed to support time-dependent data, which makes it possible to present animations alongside static scenes. For example, this animation shows one of the time-dependent visualizations.

Together, the resampling workflow and the scene viewer help bridge the gap between large-scale simulation output and an interactive web experience.