# Extract connected components from polydata structures

**URL:** <https://discourse.slicer.org/t/extract-connected-components-from-polydata-structures/12673>\
**Category:** Development\
**Tags:** slicerrt\
**Created:** [July 22, 2020, 9:33am UTC](https://discourse.slicer.org/t/extract-connected-components-from-polydata-structures/12673 "2020-07-22T09:33:32Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![loubna](https://avatars.discourse-cdn.com/v4/letter/l/cab0a1/32.png) [@loubna](https://discourse.slicer.org/u/loubna)\
**Post date:** [July 22, 2020, 9:33am UTC](https://discourse.slicer.org/t/extract-connected-components-from-polydata-structures/12673/1 "2020-07-22T09:33:32Z")

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Hi;

Is there any way to extract connected components from a set of planar contours (polydata)?

As shown in attached figure, I have two structures and I want to extract each of them as one component.

I have found this filter vtkPolydataConnectivityFilter, but it seems like it works on meshes.

Thank’s in advance

![components](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/8/0/80b256288f21c8e9f485344432f2dd628c392e9f.png)

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [July 22, 2020, 2:18pm UTC](https://discourse.slicer.org/t/extract-connected-components-from-polydata-structures/12673/2 "2020-07-22T14:18:12Z")

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Polydata = surface mesh, so vtkPolydataConnectivityFilter is the right filter to use. Of course you need to connect the planar contours to form closed surfaces.