# There is a question about vtk BooleanOperation PolyDataFilter
**URL:** https://discourse.vtk.org/t/there-is-a-question-about-vtk-booleanoperation-polydatafilter/9333
**Category:** Support
**Created:** [September 13, 2022, 2:11am UTC](https://discourse.vtk.org/t/there-is-a-question-about-vtk-booleanoperation-polydatafilter/9333 "2022-09-13T02:11:47Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Dwight98](https://discourse.vtk.org/u/Dwight98)
#### Post date: [September 13, 2022, 2:11am UTC](https://discourse.vtk.org/t/there-is-a-question-about-vtk-booleanoperation-polydatafilter/9333/1 "2022-09-13T02:11:47Z")
I have a strange problem with vtk for Boolean arithmetic，When i use the intersection operation, the result I get is as shown in the following figure
when i use the union operation,the result i get is as shown in the following figure
Compare the results in the two images above, It’s like getting the exact opposite result。
Why is this happening?Sincerely hope that seniors can answer my question!My biggest thanks！
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### Author:  [@ljx006barbatos](https://discourse.vtk.org/u/ljx006barbatos)
#### Post date: [May 2, 2023, 11:30am UTC](https://discourse.vtk.org/t/there-is-a-question-about-vtk-booleanoperation-polydatafilter/9333/2 "2023-05-02T11:30:53Z")
I met exactly the same problem.
Have u found a solution?
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### Author:  [@Jishnu](https://discourse.vtk.org/u/Jishnu)
#### Post date: [May 4, 2023, 12:39pm UTC](https://discourse.vtk.org/t/there-is-a-question-about-vtk-booleanoperation-polydatafilter/9333/3 "2023-05-04T12:39:31Z")
Without providing code, it is difficult to answer what is happening.