# VTK\_TRIANGLE 97 with less than three points, but VTK\_TRIANGLE needs at least three points

**URL:** <https://discourse.slicer.org/t/vtk-triangle-97-with-less-than-three-points-but-vtk-triangle-needs-at-least-three-points/14587>\
**Category:** Development\
**Created:** [November 13, 2020, 3:12pm UTC](https://discourse.slicer.org/t/vtk-triangle-97-with-less-than-three-points-but-vtk-triangle-needs-at-least-three-points/14587 "2020-11-13T15:12:49Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Anish\_Basnet](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/anish_basnet/32/7988_2.png) [@Anish\_Basnet](https://discourse.slicer.org/u/Anish_Basnet)\
**Post date:** [November 13, 2020, 3:12pm UTC](https://discourse.slicer.org/t/vtk-triangle-97-with-less-than-three-points-but-vtk-triangle-needs-at-least-three-points/14587/1 "2020-11-13T15:12:49Z")

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Hello everyone,  
I’d like to find intersection between two different sources. And later on apply it to a poly data that is extracted from a model node and a cube source.  
I was looking for a way to do it and I found a extension: [https://github.com/zippy84/vtkbool](https://github.com/zippy84/vtkbool).

I also found an example that uses the extension here: [https://lorensen.github.io/VTKExamples/site/Cxx/PolyData/PolyDataBooleanOperationFilter/](https://lorensen.github.io/VTKExamples/site/Cxx/PolyData/PolyDataBooleanOperationFilter/)

I am trying to test the intersection between two sphere sources, but I am getting a warning and the slicer crashes.

'Warning: In /home/anish/3D\_Slicer\_Code/Code\_with\_changes/Build/VTK/Common/DataModel/vtkPolyData.cxx, line 1021  
vtkPolyData (0x55ac4ab977d0): Building VTK\_TRIANGLE 115 with less than three points, but VTK\_TRIANGLE needs at least three points. Check the input.

error: [/home/anish/3D\_Slicer\_Code/Code\_with\_changes/Build/Slicer-build/bin/./SlicerApp-real] exit abnormally - Report the problem.

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<div class="post-metadata">

**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:** [November 13, 2020, 4:14pm UTC](https://discourse.slicer.org/t/vtk-triangle-97-with-less-than-three-points-but-vtk-triangle-needs-at-least-three-points/14587/2 "2020-11-13T16:14:21Z")

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It seems like the input polydata is corrupted. How did you generate it?  
Maybe you can fix it by using Cleaner option in Surface Toolbox module.