# Obtaining curvature of a surface from unstructured grid in paraview

**URL:** https://discourse.paraview.org/t/obtaining-curvature-of-a-surface-from-unstructured-grid-in-paraview/4733
**Category:** ParaView Support
**Created:** [July 1, 2020, 6:17pm UTC](https://discourse.paraview.org/t/obtaining-curvature-of-a-surface-from-unstructured-grid-in-paraview/4733 "2020-07-01T18:17:45Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Shruti](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/s/59ef9b/32.png) [@Shruti](https://discourse.paraview.org/u/Shruti)
#### Post date: [July 1, 2020, 6:17pm UTC](https://discourse.paraview.org/t/obtaining-curvature-of-a-surface-from-unstructured-grid-in-paraview/4733/1 "2020-07-01T18:17:45Z")

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Dear Paraview users,

I have some results for a surface in paraview in the form of an unstructured grid, and I want to obtain curvature from it. So far, I have tried using the Delaunay2D filter, then the smooth filter and then the curvature option. However, the curvature results are not smooth (image attached below), there is a lot of discontinuity and sharp increase near elements that are small, or near the edges of the surface. Is there a filter I can use to improve the results? Or is there a different approach that I can try?

I have also tried the Extract Surface Filter + Smooth Filter + Curvature. The curvature for this case is of the order of 10^5, as opposed to order of 10 for the previous case (10ish is a more reasonable number, I do have a fairly smooth surface). I looked up the guide for this filter, but couldn’t figure out what could be wrong. I’m also not sure which of the two, Delaunay2D vs ExtractSurface is a better suited filter for this case. Any suggestions?

In addition, I also have access to xyz point data in a text file for this surface, which I am mentioning, in case that is a better way to proceed to obtain curvature. So far, I have only tried delaunay filter for that, as I am not aware if there is a better way to proceed for this case.

 ![image](https://discourse.paraview.org/uploads/default/original/2X/7/749443e98439bc37b4697e8a7adbe1ac589f7472.jpeg)

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### Author: ![Andrew\_Maclean](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/a/e56c9b/32.png) [@Andrew\_Maclean](https://discourse.paraview.org/u/Andrew_Maclean)
#### Post date: [July 4, 2020, 8:47am UTC](https://discourse.paraview.org/t/obtaining-curvature-of-a-surface-from-unstructured-grid-in-paraview/4733/2 "2020-07-04T08:47:47Z")

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You may get some ideas from this topic: [https://discourse.vtk.org/t/vtkcurvatures-yields-unreasonably-large-values-along-borders/2527](https://discourse.vtk.org/t/vtkcurvatures-yields-unreasonably-large-values-along-borders/2527)