[FLASH-USERS] Options for visualizing FLASH AMR output in ParaView

[Seyed Mohammadamin Taleghani]

Dear FLASH community,

Thank you for the replies and suggestions regarding visualization. While
many suggested using VisIt or custom Python scripts, I would like to share
a method for creating *XDMF outputs* directly from FLASH, making the data
fully compatible with *ParaView*.

I have tested this method with *FLASH 4.8*. Below are the implementation
steps.
Part 1: Source Code Setup

   1.

   *Extract Grid_writeDomain Subroutines:* Extract the attached
   Grid_writeDomain_patch.zip folder into your main FLASH directory. This
   will automatically place the new subroutine Grid_writeDomain.F90 into
   the appropriate paramesh and UG directories.
   2.

   *Update Grid Makefile:* Open source/Grid/Makefile and add
   Grid_writeDomain.o to the list of object files.
   3.

   *Update Grid Interface:* Open source/Grid/Grid_interface.F90 and add the
   following interface block:

   interface Grid_writeDomain
     subroutine Grid_writeDomain(fileNumber)
       integer, optional, intent(IN) :: fileNumber
     end subroutine Grid_writeDomainend interface


Part 2: Simulation Directory Setup

   4.

   *Copy Driver Files:* Copy the following files from source/Driver/ to
   your specific simulation directory (if they aren't there already):
   -

      Driver_initFlash.F90
      -

      Driver_evolveFlash.F90
      5.

   *Modify Driver_initFlash.F90:*
   -

      Add Grid_writeDomain to the use statement:

      use Grid_interface, ONLY : ..., Grid_writeDomain

      -

      Add the call after call IO_outputInitial(dr_nbegin, dr_initialSimTime)
      :

      call Grid_writeDomain()

      6.

   *Modify Driver_evolveFlash.F90:*
   -

      Add Grid_writeDomain to the use statement:

      use Grid_interface, ONLY : ..., Grid_writeDomain

      -

      Add the call before call Timers_stop("io"):

      #ifdef FLASH_GRID_PARAMESH
        call Grid_writeDomain()
      #endif


Part 3: Compilation and Post-Processing

   7.

   *Update Makefile.h:* Open the Makefile.h used for your site and modify
   the HDF5 paths:
   -

      *Add* the API flag below CCFLAGS_HDF5:

      FFLAGS_HDF5 = -I${HDF5_PATH}/include -DH5_USE_16_API

      -

      *Change* LIB_HDF5 to:

      LIB_HDF5 = -L${HDF5_PATH}/lib -lhdf5_fortran -lhdf5 -lz

      8.

   *Run Simulation:* Compile and run your simulation. You will see new grid
   files generated in your run directory with the naming convention
   _hdf5_grd_xxxx (or _hdf5_grd_0000 if using UG).
   9.

   *Generate XDMF:*
   -

      Install *FlashKit* (instructions here
      <https://flashkit.readthedocs.io/en/main/tutorial/introduction.html#let-s-get-started>
      ).
      -

      Run the following command in your output directory:

      flashkit create xdmf --auto

      -

      This generates an .xmf file linking your .plt and .grd files.
      10.

   *Visualize:* Ensure the generated XDMF, .plt, and .grd files are in the
   same directory, then open the XDMF file in *ParaView*.

If you run into any issues implementing this, feel free to email me.

Best regards,

Seyed


On Thu, Feb 5, 2026 at 11:16 AM Seyed Mohammadamin Taleghani <
mtalegha at umd.edu> wrote:

> Dear FLASH Users,
>
> I am running an AMR simulation with FLASH 4.8 (PARAMESH) and would like to
> visualize the results in ParaView.
>
> I would like to ask the community about the recommended or supported
> workflows for using ParaView with FLASH AMR output. If there is existing
> documentation, example scripts, or recommended approaches, I would greatly
> appreciate pointers.
>
> Thank you very much for your time and help.
>
> Best regards,
>
> Seyed
>
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