# When using vtkUnstructuredGrid, how can I not display the internal cells

**URL:** https://discourse.vtk.org/t/when-using-vtkunstructuredgrid-how-can-i-not-display-the-internal-cells/7102
**Category:** Support
**Created:** [November 8, 2021, 3:25am UTC](https://discourse.vtk.org/t/when-using-vtkunstructuredgrid-how-can-i-not-display-the-internal-cells/7102 "2021-11-08T03:25:40Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![KeyboardMan](https://discourse.vtk.org/user_avatar/discourse.vtk.org/keyboardman/32/968_2.png) [@KeyboardMan](https://discourse.vtk.org/u/KeyboardMan)
#### Post date: [November 8, 2021, 3:25am UTC](https://discourse.vtk.org/t/when-using-vtkunstructuredgrid-how-can-i-not-display-the-internal-cells/7102/1 "2021-11-08T03:25:40Z")

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![cells](https://discourse.vtk.org/uploads/default/original/2X/c/c8d712caa78c18d5f32c794d1be2205b3e0db5ea.png)  
In this scenario, the number of cell reaches 7000000。  
This caused the rendering to be very slow, and it was impossible to see the internal structure.

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### Author: ![Francois\_Mazen](https://discourse.vtk.org/user_avatar/discourse.vtk.org/francois_mazen/32/3290_2.png) [@Francois\_Mazen](https://discourse.vtk.org/u/Francois_Mazen)
#### Post date: [November 9, 2021, 1:01pm UTC](https://discourse.vtk.org/t/when-using-vtkunstructuredgrid-how-can-i-not-display-the-internal-cells/7102/2 "2021-11-09T13:01:09Z")

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You can try to extract the surface with the [vtkExtractSurface](https://vtk.org/doc/nightly/html/classvtkExtractSurface.html) filter.