phasicFlow/utilities/pFlowToVTK

pFlowToVTK Utility

Overview

pFlowToVTK is a utility for converting phasicFlow simulation data into VTK (Visualization Toolkit) file format. This enables visualization of simulation results in applications like ParaView. The utility handles two primary types of data:

1. Particle Data (pointField) - Converts particle properties such as position, velocity, forces, etc.
2. Geometry Data (triSurfaceField) - Converts surface geometries and their properties

Basic Usage

pFlowToVTK [OPTIONS]

After simulation is complete, run this command from the case directory to convert all simulation data to VTK format, which will be stored in the ./VTK/ folder.

Command Line Options

Option	Description
--no-geometry	Skip conversion of geometry data to VTK format
--no-particles	Skip conversion of particle data to VTK format
-b, --binary	Write VTK files in binary format (default is ASCII). Using binary format accelerates conversion (5-10x) and visualization in ParaView
-o, --out-folder <path>	Specify the output directory path (default: ./VTK/)
-s, --separate-surfaces	Create separate files for each sub-surface in geometry
-f, --fields <field1> <field2>...	Specify which particle fields to convert (space-separated list). If not specified, all fields are converted
-t, --time <times>	Process only specific time folders. Accepts multiple formats: - Space-separated list of times (e.g., 0.1 0.2 0.3) - Strided range with format <begin>:<stride>:<end> (e.g., 0.1:0.1:0.5) - Interval with format <begin>:<end> (e.g., 0.1:0.5)
-h, --help	Display help message with all available options

Examples

Convert all data with default settings:

pFlowToVTK

Convert only geometry data:

pFlowToVTK --no-particles

Convert only particle data in binary format:

pFlowToVTK --no-geometry --binary

Convert specific fields for particles:

pFlowToVTK -f velocity diameter contactForce

Convert data for specific time steps:

pFlowToVTK -t 0.1 0.2 0.3

Convert data for a range of time steps:

pFlowToVTK -t 0.1:0.1:1.0

Write output to a custom directory:

pFlowToVTK -o /path/to/custom/output

Output Structure

The utility creates the following directory structure:

simulationCase/
├── 0/              # Contains the initial time step data
├── 0.1/            # time-folder for simulation data at 0.1 s
├── 0.2/            # time-folder for simulation data at 0.2 s
├── caseSetup/      # Contains the case setup files
├── settings/       # Contains the settings files
└── VTK/
    ├── geometry/           # Contains VTK files for geometry
    │   └── surface-*.vtk   # Geometry at different time steps
    └── particles/          # Contains VTK files for particles
        └── particles-*.vtk # Particle data at different time steps

Additionally, the utility generates .vtk.series files in the VTK root folder, which can be used by ParaView for loading time series data automatically:

VTK/
├── particles.vtk.series
└── surface.vtk.series  # (and possibly other surface names if --separate-surfaces is used)

Recommendations

• Use binary format (-b flag) for large simulations to significantly improve conversion speed and reduce file size
• For complex geometries with multiple sub-surfaces, consider using -s flag to keep surfaces in separate files for better visualization
• When working with large datasets, use the -t option to convert only the time steps you need to visualize

See Also

Related Utilities

• tutorials: Contains example cases and step-by-step guides for using phasicFlow
• particlesPhasicFlow: Creates the initial fields for particles
• geometryPhasicFlow: Creates the geometry
• postprocessPhasicFlow: Tool for performing various cell-based averaging on fields