# PassThroughPointIds for vtkExtractCells

**URL:** https://discourse.vtk.org/t/passthroughpointids-for-vtkextractcells/15262
**Category:** Development
**Tags:** code, proposal
**Created:** [February 11, 2025, 12:04pm UTC](https://discourse.vtk.org/t/passthroughpointids-for-vtkextractcells/15262 "2025-02-11T12:04:56Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![leonschropp](https://discourse.vtk.org/user_avatar/discourse.vtk.org/leonschropp/32/9800_2.png) [@leonschropp](https://discourse.vtk.org/u/leonschropp)
#### Post date: [February 11, 2025, 12:04pm UTC](https://discourse.vtk.org/t/passthroughpointids-for-vtkextractcells/15262/1 "2025-02-11T12:04:56Z")

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Hi, I’m using the filter provided in **vtkExtractCells.h** for a Project at work, where I need to extract all 2D cells from an `vtkUnstructuredGrid `and seperate both remaining `vtkUnstructuredGrid `by their connected components. However, I need to track keep of the indices of the points of the `vtkUnstructuredGrid`. I tested this filter quite a bit and I think at the current state **it doesn’t preserve the indices of the points.**

It’s great that one can still access the original cellids after using this filter by setting `PassThroughCellIdsOn()`, but, at the same time, it makes me sad, that there is no similar way to access the point ids. It would be really useful for me to have this functionality, just like it is provided in **vtkUnstructuredGridGeometryFilter.h** via `PassThroughPointIdsOn()`.

Is this funtionality planned to come in a new release anyway maybe ?

I would also be willing to add that functionality to vtkExtractCells.h myself, but I suspect it would be much faster if somebody more experienced would do this, as I’m just a working student.

Cheers, Leon