frd2vtu

Convert CalculiX binary .frd files to VTK .vtu files for ParaView and other VTK tools. Inspired by ccx2paraview.

Overview

frd2vtu reads CalculiX binary FRD output (from *element output / *node output) and writes VTK unstructured grids with field data per timestep. Multiple files can be converted in parallel.

Installation

pip install frd2vtu

Development install:

uv pip install -e ".[dev]"

Usage

Convert one or more FRD files (parallel by default; output goes next to each input unless --output-dir is set):

frd2vtu convert model.frd
frd2vtu convert run1.frd run2.frd --output-dir ./vtu
frd2vtu convert *.frd --no-parallel

Prepare a CalculiX .inp for binary FRD output (*node file / *el file → *node output / *element output):

frd2vtu iprep model.inp
frd2vtu iprep model.inp --output-dir ./prepared

Plot VTU point arrays (writes a PNG beside each file):

frd2vtu_plot model.vtu
frd2vtu_plot a.vtu b.vtu --no-parallel

CLI help is tree-shaped; export the command schema as JSON:

frd2vtu --help
frd2vtu --json

Python API

from frd2vtu import frdbin2vtu, frd2vtu

grid = frdbin2vtu("model.frd", output_dir="out/")
frd2vtu(["run1.frd", "run2.frd"], parallel=True, output_dir="out/")

Examples

Screenshots from the CalculiX test directory:

License

MIT — see LICENSE.

Test coverage

Tested against binary CalculiX FRD files in test/frds/ (ASCII header-only stubs are omitted). Regenerate with make readme-coverage.