# Converting triangular polydata to quadratic

**URL:** https://discourse.vtk.org/t/converting-triangular-polydata-to-quadratic/8744
**Category:** Support
**Created:** [June 16, 2022, 9:33am UTC](https://discourse.vtk.org/t/converting-triangular-polydata-to-quadratic/8744 "2022-06-16T09:33:10Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Danial\_Mohajery](https://discourse.vtk.org/user_avatar/discourse.vtk.org/danial_mohajery/32/4294_2.png) [@Danial\_Mohajery](https://discourse.vtk.org/u/Danial_Mohajery)
#### Post date: [June 16, 2022, 9:33am UTC](https://discourse.vtk.org/t/converting-triangular-polydata-to-quadratic/8744/1 "2022-06-16T09:33:10Z")

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Hi,

I have segmentation data that I use with MarchingCubes to make an isosurface. Then I use this surface with the probe filter to map intensity values on the mesh. The resulting geometry has triangular elements (see the figures below) but I want to convert it to quadratic elements. I tried vtkQuadricDecimation but it only converts very few elements and if I increase the decimation, the geometry messes up :/. The only remaining option is to convert cell by cell. Yet, the points are not organized in counter clock wise or clock wise necessarily(?). So, I am open to suggestions :))

 ![1](https://discourse.vtk.org/uploads/default/original/2X/f/f9b5b00fc9f20858691587fb4412bf10420fcd5a.png)  
 ![2](https://discourse.vtk.org/uploads/default/original/2X/d/d885a7cf2840998f519c172d5b0625315d819a32.png)