# How to get specific number of seed points using seedwidgetwithcustomcallback?

**URL:** https://discourse.vtk.org/t/how-to-get-specific-number-of-seed-points-using-seedwidgetwithcustomcallback/2814
**Category:** Support
**Created:** [March 13, 2020, 11:23am UTC](https://discourse.vtk.org/t/how-to-get-specific-number-of-seed-points-using-seedwidgetwithcustomcallback/2814 "2020-03-13T11:23:51Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Pooja](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/p/a5b964/32.png) [@Pooja](https://discourse.vtk.org/u/Pooja)
#### Post date: [March 13, 2020, 11:23am UTC](https://discourse.vtk.org/t/how-to-get-specific-number-of-seed-points-using-seedwidgetwithcustomcallback/2814/1 "2020-03-13T11:23:51Z")

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Hello,

I used seedwidgetwithcustomcallback to get seed points of dicom image.  
But I need only 3 seeds and after that it should not take new point.  
Could someone please tell me how to do it?

It seems PlacePointEvent used in SeedRepresentation class can take 1000 number of seeds.  
Is there any way to change it?

Thanks in advance.

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### Author: ![flaviu2](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/f/74df32/32.png) [@flaviu2](https://discourse.vtk.org/u/flaviu2)
#### Post date: [March 13, 2020, 3:07pm UTC](https://discourse.vtk.org/t/how-to-get-specific-number-of-seed-points-using-seedwidgetwithcustomcallback/2814/3 "2020-03-13T15:07:10Z")

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In your vtkSeedCallback class, you can count your 3 seed points, and if this condition is accomplished, the you can avoid vtkCommand::PlacePointEvent event.

It is just an idea … or, remove observers if seed point is great or equal with 3.