VTK Metadata Export

ViennaPS supports exporting metadata to VTK output files. This feature allows users to embed additional simulation-specific and domain-specific information into the VTK files generated during surface, hull, or volume mesh output. The metadata is useful for post-processing, debugging, visualization, and reproducibility of simulation results.

Metadata can be selectively included in VTK output by setting a metadata level, which controls the amount and type of information written. Metadata export is configured at the Domain level using the following static method:

Domain<NumericType, D>::enableMetaData(const MetaDataLevel level = MetaDataLevel::PROCESS);

Once enabled, metadata will be attached to all future VTK output from any domain instance during the current execution.

Metadata Levels

The MetaDataLevel enum defines the available levels of metadata:

Level Description
NONE No metadata is written to VTK files.
GRID Domain-specific metadata only (e.g., grid spacing, boundary conditions).
PROCESS Includes domain metadata and parameters from the most recently applied process.
FULL Includes all available metadata, such as advection model settings, ray tracing parameters, etc.

The default level when enabling metadata is MetaDataLevel::PROCESS.

Usage Example 

// Enable metadata export with full detail
Domain<double, 3>::enableMetaData(MetaDataLevel::FULL);

// Create domain and apply process
auto domain = Domain<double, 3>::New();
...
Process<double, 3> process(domain, model);
process.apply();

// Write output
domain.saveSurfaceMesh("output_surface.vtp"); // Surface mesh with metadata

The resulting VTK file will now contain metadata including grid spacing, boundary conditions, and all relevant parameters from the applied process.

Python:

 
# Enable metadata export with full detail
vps.Domain.enableMetaData(vps.MetaDataLevel.FULL)

# Create domain and apply process
domain = vps.Domain()
...
process = vps.Process(domain, model)
process.apply()

# Write output
domain.saveSurfaceMesh("output_surface.vtp") # Surface mesh with metadata

Process Metadata Behavior

  • Metadata at the PROCESS or FULL level always reflects the most recently applied process via .apply().
  • When a new process is applied to a domain, the previously stored process metadata is cleared and replaced with the current one.
  • Only one set of process metadata is retained per domain at any time.

Affected Output Types

Metadata is supported in the following mesh outputs:

  • Surface mesh (.vtp)
  • Hull mesh (.vtp)
  • Volume mesh (.vtu)

Each writer automatically includes the metadata based on the current global setting.

Notes

  • The metadata system is static and global. Once enabled, it affects all domain instances during the simulation run.
  • For deterministic and reproducible output, it is recommended to enable metadata at the start of the simulation.