# how to use plotOnIntersectionCurve on octree mesh

**URL:** https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260
**Category:** ParaView Support
**Tags:** vtk
**Created:** [November 15, 2023, 1:53pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260 "2023-11-15T13:53:23Z")
**Posts on this page:** 10
**Page:** 1

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### Author: ![garcfd](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/g/ccd318/32.png) [@garcfd](https://discourse.paraview.org/u/garcfd)
#### Post date: [November 15, 2023, 1:53pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/1 "2023-11-15T13:53:23Z")

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Im basically trying to plot the surface profile of pressure an an airfoil surface. I have done this before using rectilinear mesh and the process works ok. Now Im moving to an unstructured octree mesh. Im using a distance field to get the airfoil surface, and then using plotOnIntersectionCurve to get the surface pressure profile. This works ok except that the PlotOnIntersectionCurve settings, it includes all the Blocks as seperate datasets (eg Dataset0 to Dataset8) which means loads of flow variables to sort through and select/deselect for the plot options. I want just one dataset ideally, I dont know how/why they have got split into different blocks/datasets, and how to avoid that.

In Paraview 3.98 it looks like this

 ![Capture2](https://discourse.paraview.org/uploads/default/original/2X/8/87f6ba7c44990f3554df1ca063781bc35f0c1591.jpeg)

In paraview 5.11 it looks like this (several line segments are created)

 ![Capture3](https://discourse.paraview.org/uploads/default/original/2X/9/9c6689fc510f139b2b0380685d4eff221b096dc7.jpeg)

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### Author: ![Christos\_Tsolakis](https://discourse.paraview.org/user_avatar/discourse.paraview.org/christos_tsolakis/32/4450_2.png) [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [November 20, 2023, 11:09pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/2 "2023-11-20T23:09:02Z")

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You could try to apply `MergeCells` before applying the `PlotOnIntersectionCurves` filter.

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<div class="post-metadata">

### Author: ![garcfd](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/g/ccd318/32.png) [@garcfd](https://discourse.paraview.org/u/garcfd)
#### Post date: [November 20, 2023, 11:18pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/3 "2023-11-20T23:18:52Z")

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thanks Christos, I will give that a try.

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<div class="post-metadata">

### Author: ![garcfd](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/g/ccd318/32.png) [@garcfd](https://discourse.paraview.org/u/garcfd)
#### Post date: [November 29, 2023, 12:14pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/4 "2023-11-29T12:14:01Z")

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Merge Cells, I cannot see that filter…?

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<div class="post-metadata">

### Author: ![Christos\_Tsolakis](https://discourse.paraview.org/user_avatar/discourse.paraview.org/christos_tsolakis/32/4450_2.png) [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [November 29, 2023, 1:44pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/5 "2023-11-29T13:44:15Z")

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My bad ! The correct name is `Merge Blocks`.

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<div class="post-metadata">

### Author: ![garcfd](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/g/ccd318/32.png) [@garcfd](https://discourse.paraview.org/u/garcfd)
#### Post date: [November 29, 2023, 2:07pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/6 "2023-11-29T14:07:58Z")

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Thanks - yes I can see “Merge Blocks”, but unfortunately (for me) its grey, so I cannot select it.

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### Author: ![Christos\_Tsolakis](https://discourse.paraview.org/user_avatar/discourse.paraview.org/christos_tsolakis/32/4450_2.png) [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [November 29, 2023, 2:22pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/7 "2023-11-29T14:22:43Z")

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Can you share the data via [wetransfer](https://wetransfer.com/) or some other method ?

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<div class="post-metadata">

### Author: ![garcfd](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/g/ccd318/32.png) [@garcfd](https://discourse.paraview.org/u/garcfd)
#### Post date: [November 29, 2023, 2:26pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/8 "2023-11-29T14:26:53Z")

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yes sure … hold on a minute

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<div class="post-metadata">

### Author: ![garcfd](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/g/ccd318/32.png) [@garcfd](https://discourse.paraview.org/u/garcfd)
#### Post date: [November 29, 2023, 2:30pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/9 "2023-11-29T14:30:48Z")

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Here is my results file that I am working with…

> **[octree.vtk](https://drive.google.com/file/d/15hIhnsOlS8HmUm0JpouWUtlTzJnMuOI-/view?usp=sharing)**
>
> Google Drive file.

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<div class="post-metadata">

### Author: ![Christos\_Tsolakis](https://discourse.paraview.org/user_avatar/discourse.paraview.org/christos_tsolakis/32/4450_2.png) [@Christos\_Tsolakis](https://discourse.paraview.org/u/Christos_Tsolakis)
#### Post date: [November 30, 2023, 1:56pm UTC](https://discourse.paraview.org/t/how-to-use-plotonintersectioncurve-on-octree-mesh/13260/10 "2023-11-30T13:56:01Z")

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Thanks you for sharing . Unfortunately, I haven’t been able to resolve the issue. I attach a state file in case someone else wants to give it a try.  
[octree\_state.pvsm](https://discourse.paraview.org/uploads/short-url/syWZishhCIBiI4UUxlEwI8v7DlZ.pvsm) (1.1 MB)