# \#file-formats **URL:** https://discourse.vtk.org/tag/file-formats/2.md [Latest](https://discourse.vtk.org/latest.md) · [Categories](https://discourse.vtk.org/categories.md) · [Tags](https://discourse.vtk.org/tags.md) --- ## [Changes in VTK lagacy format from V3.0 to V5.0 - causes cell offset error](https://discourse.vtk.org/t/changes-in-vtk-lagacy-format-from-v3-0-to-v5-0-causes-cell-offset-error/16541)
**Author:** [@KimF](https://discourse.vtk.org/u/KimF)\ **Replies:** 8\ **Last updated:** [September 23, 2026, 10:48pm UTC](https://discourse.vtk.org/t/changes-in-vtk-lagacy-format-from-v3-0-to-v5-0-causes-cell-offset-error/16541 "2026-09-23T22:48:45Z")
I’m trying to write a legacy VTK file for an unstructured tetrahedral grid. All of the VTK documentation I can find suggests that the cell linkage block should have a header as follows CELLS \<# cells\> \ **Author:** [@jobojeha](https://discourse.vtk.org/u/jobojeha)\ **Replies:** 0\ **Last updated:** [May 12, 2026, 9:15am UTC](https://discourse.vtk.org/t/xmlunstructuredgridreader-ignores-already-existing-array-names-in-time-series/16414 "2026-05-12T09:15:28Z") I’ve been working with VTK UnstructuredGrid files that contain time series. In your external test files I found cube-with-time.vtu which is essentially doing the same thing. Similar to how its described here Field Data a… --- ## [vtkExodusIIReader: Potential Memory Bugs](https://discourse.vtk.org/t/vtkexodusiireader-potential-memory-bugs/16382)
**Author:** [@Landon-Huking](https://discourse.vtk.org/u/Landon-Huking)\ **Replies:** 2\ **Last updated:** [April 21, 2026, 3:39pm UTC](https://discourse.vtk.org/t/vtkexodusiireader-potential-memory-bugs/16382 "2026-04-21T15:39:03Z")
Intro Hi! I have been fuzzing VTK file readers and have potentially fond some memory bugs in the vtkExodusIIReader module. Fuzzing Setup All fuzzing was done with AFL++ using a from source build of VTK with AFL instrume… --- ## [VTK reporting potential vulnerabilities](https://discourse.vtk.org/t/vtk-reporting-potential-vulnerabilities/15796)
**Author:** [@harrypantazis](https://discourse.vtk.org/u/harrypantazis)\ **Replies:** 3\ **Last updated:** [April 17, 2026, 11:39pm UTC](https://discourse.vtk.org/t/vtk-reporting-potential-vulnerabilities/15796 "2026-04-17T23:39:14Z")
Greetings, I have been fuzzing an open-source application which depends on VTK (9.5) as part of a security code audit and have identified a series of memory errors for a specific filetype parser in VTK. Which would be … --- ## [How to overlay a vector field on a molecule, with output to file for use in ParaView](https://discourse.vtk.org/t/how-to-overlay-a-vector-field-on-a-molecule-with-output-to-file-for-use-in-paraview/16357)
**Author:** [@jzwanzig](https://discourse.vtk.org/u/jzwanzig)\ **Replies:** 0\ **Last updated:** [March 25, 2026, 2:10pm UTC](https://discourse.vtk.org/t/how-to-overlay-a-vector-field-on-a-molecule-with-output-to-file-for-use-in-paraview/16357 "2026-03-25T14:10:46Z")
Hello, I am generating vector field data in an ab initio physics code, and I am able to convert it to a vtkStructuredGrid and display it nicely in ParaView; I am also able to generate a vtkMolecule and display that nicel… --- ## [VTKHDF: Clarifying a distinction between MB and PDC](https://discourse.vtk.org/t/vtkhdf-clarifying-a-distinction-between-mb-and-pdc/16306)
**Author:** [@nncarlson](https://discourse.vtk.org/u/nncarlson)\ **Replies:** 3\ **Last updated:** [March 24, 2026, 1:59pm UTC](https://discourse.vtk.org/t/vtkhdf-clarifying-a-distinction-between-mb-and-pdc/16306 "2026-03-24T13:59:55Z")
When describing the difference between MB and PDC datasets, the 2.6 spec says: “For PDC, a group in the assembly that is \[…\] a softlink represents a dataset index associated to its parent node.” I don’t understand wh… --- ## [VTKHDF roadmap](https://discourse.vtk.org/t/vtkhdf-roadmap/13257)
**Author:** [@lgivord](https://discourse.vtk.org/u/lgivord)\ **Replies:** 26\ **Last updated:** [March 21, 2026, 2:54pm UTC](https://discourse.vtk.org/t/vtkhdf-roadmap/13257 "2026-03-21T14:54:07Z")
THIS POST IS OUTDATED AND ONLY KEPT FOR HISTORIC PURPOSES Please consult the up to date roadmap here: VTKHDF: Implementation Status - VTK documentation ==================================================================… --- ## [First release of fVTKHDF: A modern Fortran library for writing VTKHDF files](https://discourse.vtk.org/t/first-release-of-fvtkhdf-a-modern-fortran-library-for-writing-vtkhdf-files/16304)
**Author:** [@nncarlson](https://discourse.vtk.org/u/nncarlson)\ **Replies:** 7\ **Last updated:** [March 2, 2026, 1:35pm UTC](https://discourse.vtk.org/t/first-release-of-fvtkhdf-a-modern-fortran-library-for-writing-vtkhdf-files/16304 "2026-03-02T13:35:48Z")
If you’re a Fortran’er, this may be of interest to you. I’ve just published the first release of fVTKHDF, a high-level, object-oriented Fortran library for writing VTKHDF files. It currently supports UnstructuredGrid (… --- ## [legacy file format: data type and version](https://discourse.vtk.org/t/legacy-file-format-data-type-and-version/16299)
**Author:** [@MarDiehl](https://discourse.vtk.org/u/MarDiehl)\ **Replies:** 6\ **Last updated:** [March 2, 2026, 9:27am UTC](https://discourse.vtk.org/t/legacy-file-format-data-type-and-version/16299 "2026-03-02T09:27:59Z")
VTK 9.6.0 has a weird change behavior when it comes to the legacy file format: The data type for OFFSETS and CONNECTIVITY of POLYDATA is vtktypeint64 after creation (using the Python bindings) but changes to long when sa… --- ## [Clarification about temporal MB or PDC VTKHDF datasets](https://discourse.vtk.org/t/clarification-about-temporal-mb-or-pdc-vtkhdf-datasets/16305)
**Author:** [@nncarlson](https://discourse.vtk.org/u/nncarlson)\ **Replies:** 3\ **Last updated:** [February 26, 2026, 9:15am UTC](https://discourse.vtk.org/t/clarification-about-temporal-mb-or-pdc-vtkhdf-datasets/16305 "2026-02-26T09:15:59Z")
I had been operating under the assumption that in a MB or PDC VTKHDF dataset some blocks could be temporal and others not (without a Steps group). However, I’m getting import errors (with MB) from paraview. Is it requir… --- ## [vtkHDF: Add support for polyhedron cells](https://discourse.vtk.org/t/vtkhdf-add-support-for-polyhedron-cells/13089)
**Author:** [@MicK7](https://discourse.vtk.org/u/MicK7)\ **Replies:** 42\ **Last updated:** [February 24, 2026, 8:57pm UTC](https://discourse.vtk.org/t/vtkhdf-add-support-for-polyhedron-cells/13089 "2026-02-24T20:57:11Z")
The idea would be to add support for polyhedral cell in a partition of unstructured grid stored in vtkHDF The partition sizing for polyhedral cells would required defining the following variables: NumberOfFaces Number… --- ## [Support for RectilinearGrids and StructuredGrids in VTKHDF file format](https://discourse.vtk.org/t/support-for-rectilineargrids-and-structuredgrids-in-vtkhdf-file-format/14283)
**Author:** [@jpmorr](https://discourse.vtk.org/u/jpmorr)\ **Replies:** 7\ **Last updated:** [February 23, 2026, 1:02pm UTC](https://discourse.vtk.org/t/support-for-rectilineargrids-and-structuredgrids-in-vtkhdf-file-format/14283 "2026-02-23T13:02:06Z")
Hi, I’m interested in using RectilinearGrids and StructuredGrids in the VTKHDF format. Since these formats are not currently supported or on the roadmap, I’ve taken a few minutes to translate some simple .vtr and .vts f… --- ## [VTKHDF and vtkGlobalPointIds](https://discourse.vtk.org/t/vtkhdf-and-vtkglobalpointids/16264)
**Author:** [@nncarlson](https://discourse.vtk.org/u/nncarlson)\ **Replies:** 3\ **Last updated:** [February 2, 2026, 2:59pm UTC](https://discourse.vtk.org/t/vtkhdf-and-vtkglobalpointids/16264 "2026-02-02T14:59:36Z")
I’m generating VTKHDF unstructured grid datasets in parallel consisting of multiple parts. Gemini tells me that if I include a vtkGlobalPointIds array in the PointData group, Paraview will use it to better stitch togeth… --- ## [Possible VTKHDF bug](https://discourse.vtk.org/t/possible-vtkhdf-bug/16255)
**Author:** [@nncarlson](https://discourse.vtk.org/u/nncarlson)\ **Replies:** 6\ **Last updated:** [January 27, 2026, 3:11pm UTC](https://discourse.vtk.org/t/possible-vtkhdf-bug/16255 "2026-01-27T15:11:27Z")
I’ve developed a VTKHDF writer for our code that is working for small development test cases, but which is causing errors in paraview for large application-like cases. I’m generating a MultiBlockDataSet file with 4 block… --- ## [vtkGLTFWriter: a working example?](https://discourse.vtk.org/t/vtkgltfwriter-a-working-example/11620)
**Author:** [@bistek](https://discourse.vtk.org/u/bistek)\ **Replies:** 6\ **Last updated:** [January 15, 2026, 8:20am UTC](https://discourse.vtk.org/t/vtkgltfwriter-a-working-example/11620 "2026-01-15T08:20:43Z")
Hello, does anybody have a working example of vtkGLTFWriter(). The documentation is very concise, and I’m trying different patterns similar to other writers, but I always get the error: Process finished with exit code … --- ## [Support PLY with texture coordinates parameters named (s, t)](https://discourse.vtk.org/t/support-ply-with-texture-coordinates-parameters-named-s-t/16197)
**Author:** [@afavray.modjaw](https://discourse.vtk.org/u/afavray.modjaw)\ **Replies:** 7\ **Last updated:** [January 14, 2026, 11:14am UTC](https://discourse.vtk.org/t/support-ply-with-texture-coordinates-parameters-named-s-t/16197 "2026-01-14T11:14:33Z")
Hello, I am using vtkPLYReader to import various PLY meshes in my project (python VTK 9.5.2). I have a problem with some PLY file formats that use external texture : the vtkPLYReader fails to parse texture coordinates … --- ## [Support export of PLY with external texture](https://discourse.vtk.org/t/support-export-of-ply-with-external-texture/16198)
**Author:** [@afavray.modjaw](https://discourse.vtk.org/u/afavray.modjaw)\ **Replies:** 2\ **Last updated:** [January 8, 2026, 3:29pm UTC](https://discourse.vtk.org/t/support-export-of-ply-with-external-texture/16198 "2026-01-08T15:29:19Z")
Hello, I am using vtkPLYReader + vtkPLYWriter to import/export various PLY meshes in my project (python VTK 9.5.2). I have a problem with some PLY file formats that use external texture : the vtkPLYWriter doesn’t write… --- ## [How does the VTKHDF reader handle HDF5 hardlink datasets?](https://discourse.vtk.org/t/how-does-the-vtkhdf-reader-handle-hdf5-hardlink-datasets/16189)
**Author:** [@nncarlson](https://discourse.vtk.org/u/nncarlson)\ **Replies:** 6\ **Last updated:** [December 19, 2025, 9:47am UTC](https://discourse.vtk.org/t/how-does-the-vtkhdf-reader-handle-hdf5-hardlink-datasets/16189 "2025-12-19T09:47:24Z")
I’d like to know how the VTKHDF reader handles a dataset that is an HDF5 hardlink to another dataset. Is it smart enough to only load the dataset into memory once and reuse that reference each time it encounters a hardli… --- ## [No "Blocks" checkbox section with VTKHDF MultiBlockDataSet format](https://discourse.vtk.org/t/no-blocks-checkbox-section-with-vtkhdf-multiblockdataset-format/16180)
**Author:** [@nncarlson](https://discourse.vtk.org/u/nncarlson)\ **Replies:** 5\ **Last updated:** [December 12, 2025, 3:20pm UTC](https://discourse.vtk.org/t/no-blocks-checkbox-section-with-vtkhdf-multiblockdataset-format/16180 "2025-12-12T15:20:43Z")
I’m looking into by-passing the TRUCHAS reader (builtin to VTK) for our custom HDF5 output by reimplementing the output using the VTKHDF file format. Each cell in the unstructured mesh is tagged with an integer that iden… --- ## [VTKHDF: 读入FieldData中的StringArray报错](https://discourse.vtk.org/t/vtkhdf-fielddata-stringarray/16154)
**Author:** [@jie\_baoer](https://discourse.vtk.org/u/jie_baoer)\ **Replies:** 2\ **Last updated:** [November 24, 2025, 8:37am UTC](https://discourse.vtk.org/t/vtkhdf-fielddata-stringarray/16154 "2025-11-24T08:37:57Z")
When I was testing vtkhdf, I found that when the read StringArray was n rows and multiple columns, an error would be prompted ERROR: In vtkHDFUtilities.cxx, line 558 (nullptr): Dataset: ndims: 2 greater than expected n… --- ## [Incorrect cell\_data shapes when reading .cas.h5 with vtkFLUENTCFFReader](https://discourse.vtk.org/t/incorrect-cell-data-shapes-when-reading-cas-h5-with-vtkfluentcffreader/16153)
**Author:** [@nmheim](https://discourse.vtk.org/u/nmheim)\ **Replies:** 4\ **Last updated:** [November 20, 2025, 10:12am UTC](https://discourse.vtk.org/t/incorrect-cell-data-shapes-when-reading-cas-h5-with-vtkfluentcffreader/16153 "2025-11-20T10:12:27Z")
Hey everyone! This is my first post here, so I apologize if its in the wrong category or otherwise not according to the rules. Happy to open this in a different place, if that helps:) I am encountering an issue when rea… --- ## [Writing a vtk legacy file in binary format with Fortran. String datafield issue](https://discourse.vtk.org/t/writing-a-vtk-legacy-file-in-binary-format-with-fortran-string-datafield-issue/16136)
**Author:** [@314tho](https://discourse.vtk.org/u/314tho)\ **Replies:** 2\ **Last updated:** [November 12, 2025, 9:10am UTC](https://discourse.vtk.org/t/writing-a-vtk-legacy-file-in-binary-format-with-fortran-string-datafield-issue/16136 "2025-11-12T09:10:47Z")
Hi everybody ! To enable the visualization with Paraview of the results of my Fortran FE code, I developed in it the generation of a vtk file as output (legacy format, either ASCII or BINARY). The vtk legacy format is q… --- ## [How to write temporal UnstructuredGrid data to a VTKHDF file with vtkHDFWriter in Python?](https://discourse.vtk.org/t/how-to-write-temporal-unstructuredgrid-data-to-a-vtkhdf-file-with-vtkhdfwriter-in-python/16096)
**Author:** [@liblaf](https://discourse.vtk.org/u/liblaf)\ **Replies:** 2\ **Last updated:** [October 15, 2025, 3:02pm UTC](https://discourse.vtk.org/t/how-to-write-temporal-unstructuredgrid-data-to-a-vtkhdf-file-with-vtkhdfwriter-in-python/16096 "2025-10-15T15:02:20Z")
Hi all, I’m trying to write a time series of vtkUnstructuredGrid data to a single VTKHDF (.vtkhdf) file using Python. Specifically, the grid topology is constant, but a point data array named “foo” changes over 100 time… --- ## [Write UnstructuredGrid in parallel](https://discourse.vtk.org/t/write-unstructuredgrid-in-parallel/16025)
**Author:** [@akaszynski](https://discourse.vtk.org/u/akaszynski)\ **Replies:** 6\ **Last updated:** [September 12, 2025, 8:52am UTC](https://discourse.vtk.org/t/write-unstructuredgrid-in-parallel/16025 "2025-09-12T08:52:48Z")
Hello, I’m attempting write out an UnstructuredGrid using vtkXMLPUnstructuredGridWriter, but I’m hitting a wall. Specifically, I can’t seem to actually write out the file in N pieces and instead it writes out the entire… --- ## [VTKHDF PartitionedDataSetCollection (PDC) file not working in Paraview](https://discourse.vtk.org/t/vtkhdf-partitioneddatasetcollection-pdc-file-not-working-in-paraview/14553)
**Author:** [@jpmorr](https://discourse.vtk.org/u/jpmorr)\ **Replies:** 5\ **Last updated:** [June 11, 2025, 1:33pm UTC](https://discourse.vtk.org/t/vtkhdf-partitioneddatasetcollection-pdc-file-not-working-in-paraview/14553 "2025-06-11T13:33:42Z")
I’m trying to create a VTKHDF file that has multiple blocks in it but I’ve not managed to do so yet. My initial question was here where I was pointed towards the documentation and given a working example file. Rather tha… --- ## [VTK to OpenVDB file format](https://discourse.vtk.org/t/vtk-to-openvdb-file-format/6322)
**Author:** [@tkeskita](https://discourse.vtk.org/u/tkeskita)\ **Replies:** 12\ **Last updated:** [June 6, 2025, 2:48pm UTC](https://discourse.vtk.org/t/vtk-to-openvdb-file-format/6322 "2025-06-06T14:48:08Z")
Hi, This post was created to summarize current status of possibilities to convert/export VTK 3D image data into OpenVDB volumetric voxel data / grid format (.vdb). This is getting to be a frequently asked question, so I… --- ## [Please document off-by-one for modern NumberOfPolys](https://discourse.vtk.org/t/please-document-off-by-one-for-modern-numberofpolys/15651)
**Author:** [@Chris\_Rorden](https://discourse.vtk.org/u/Chris_Rorden)\ **Replies:** 1\ **Last updated:** [May 20, 2025, 1:58pm UTC](https://discourse.vtk.org/t/please-document-off-by-one-for-modern-numberofpolys/15651 "2025-05-20T13:58:09Z")
Traditional ASCII and binary legacy files are documented here and here, while examples and description of the modern XML VTK file is here. However, recent VTK code will read and write variations of the old format that a… --- ## [Base64 woes & associated questions regarding how vtk reads data in the xml form](https://discourse.vtk.org/t/base64-woes-associated-questions-regarding-how-vtk-reads-data-in-the-xml-form/15517)
**Author:** [@Subject303](https://discourse.vtk.org/u/Subject303)\ **Replies:** 1\ **Last updated:** [April 19, 2025, 6:51pm UTC](https://discourse.vtk.org/t/base64-woes-associated-questions-regarding-how-vtk-reads-data-in-the-xml-form/15517 "2025-04-19T18:51:19Z")
I’m suffering at the behest of the vtk xml format and would appreciate some advice regarding what format the data should be in. So as an exercise I’m creating a vtp file that stores the coordinates of a 27 point, cube, … --- ## [Trying to view vtu or vtk file in the web](https://discourse.vtk.org/t/trying-to-view-vtu-or-vtk-file-in-the-web/14938)
**Author:** [@sridhar-mani](https://discourse.vtk.org/u/sridhar-mani)\ **Replies:** 8\ **Last updated:** [December 31, 2024, 5:35pm UTC](https://discourse.vtk.org/t/trying-to-view-vtu-or-vtk-file-in-the-web/14938 "2024-12-31T17:35:00Z")
I have been trying to view vtk or vtu file in web but unable to do so as only vtp seems to be supported. --- ## [vtkXMLUnstructuredGridReader can not read binary vtu file correctly](https://discourse.vtk.org/t/vtkxmlunstructuredgridreader-can-not-read-binary-vtu-file-correctly/15060)
**Author:** [@yiman](https://discourse.vtk.org/u/yiman)\ **Replies:** 2\ **Last updated:** [December 24, 2024, 5:44am UTC](https://discourse.vtk.org/t/vtkxmlunstructuredgridreader-can-not-read-binary-vtu-file-correctly/15060 "2024-12-24T05:44:17Z")
I have one vtu file, it has an “AppendedData” section, in this section, it contains the binary data of all cells. I can open this file without any error in paraview(I know this software also uses vtk), but If I try to re… [Next page](https://discourse.vtk.org/tag/file-formats/2.md?match_all_tags=true&page=1&tags%5B%5D=file-formats)