# About custom cutting and drawing lines

**URL:** https://discourse.vtk.org/t/about-custom-cutting-and-drawing-lines/11222
**Category:** Support
**Created:** [April 17, 2023, 2:58am UTC](https://discourse.vtk.org/t/about-custom-cutting-and-drawing-lines/11222 "2023-04-17T02:58:09Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![HWsir](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/h/9dc877/32.png) [@HWsir](https://discourse.vtk.org/u/HWsir)
#### Post date: [April 17, 2023, 2:58am UTC](https://discourse.vtk.org/t/about-custom-cutting-and-drawing-lines/11222/1 "2023-04-17T02:58:10Z")

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I plan to create a plane parallel to the screen and draw lines on this plane and then do the cutting operation.  
I have two questions.  
How do I get the normal vector of the current window plane?  
How does vtk create a plane parallel to the window screen?  
I think if the first problem is solved, the second problem should also be solved.

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### Author: ![HWsir](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/h/9dc877/32.png) [@HWsir](https://discourse.vtk.org/u/HWsir)
#### Post date: [April 18, 2023, 1:32pm UTC](https://discourse.vtk.org/t/about-custom-cutting-and-drawing-lines/11222/2 "2023-04-18T13:32:28Z")

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I have solved this problem, vtkCamera has two functions, GeteyePlaneNomal and GetViewPlaneNomal, I confused them