# Convert dataset to PolyData
**URL:** https://discourse.vtk.org/t/convert-dataset-to-polydata/6913
**Category:** Support
**Created:** [October 18, 2021, 10:47pm UTC](https://discourse.vtk.org/t/convert-dataset-to-polydata/6913 "2021-10-18T22:47:01Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@woodscn](https://discourse.vtk.org/u/woodscn)
#### Post date: [October 18, 2021, 10:47pm UTC](https://discourse.vtk.org/t/convert-dataset-to-polydata/6913/1 "2021-10-18T22:47:01Z")
How do you convert a 2D dataset to PolyData in VTK? I would use Extract Surface in Paraview, but the documentation for vtkExtractSurface seems to describe something different, and it requires a PolyData input. It may also matter that I’m starting from a MultiBlock dataset (from ExodusII, if that matters).
Thanks,
Nate
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### Author:  [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [October 19, 2021, 7:40am UTC](https://discourse.vtk.org/t/convert-dataset-to-polydata/6913/2 "2021-10-19T07:40:44Z")
vtkDataSetSurfaceFilter
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### Author:  [@woodscn](https://discourse.vtk.org/u/woodscn)
#### Post date: [October 20, 2021, 3:09pm UTC](https://discourse.vtk.org/t/convert-dataset-to-polydata/6913/3 "2021-10-20T15:09:49Z")
Edit: The equivalent code works fine in Python. It seems more likely that I botched something building the VTK library.
When I try, I get this error at runtime:
