# Filter documentation

**URL:** <https://discourse.vtk.org/t/filter-documentation/3457>\
**Category:** Development\
**Created:** [June 3, 2020, 3:37pm UTC](https://discourse.vtk.org/t/filter-documentation/3457 "2020-06-03T15:37:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![SimonFuet](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/s/e95f7d/32.png) [@SimonFuet](https://discourse.vtk.org/u/SimonFuet)\
**Post date:** [June 3, 2020, 3:37pm UTC](https://discourse.vtk.org/t/filter-documentation/3457/1 "2020-06-03T15:37:33Z")

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Hi all,

Is there an up-to-date documentation about VTK filters? i.e. a description of everything we must, should and can do when implementing a new filter…

More precisely, the ProcessRequest method needs to be reimplemented, but I can’t find any description of the different steps (REQUEST\_DATA, REQUEST\_DATA\_OBJECT, REQUEST\_INFORMATION…), what I should do at each step etc…

I’ve spent a lot of time looking at tens of existing filters to try to figure out how everything works, but at some point I’m gonna need a real documentation, which I just can’t find…

Any hint would be greatly appreciated

Simon

PS: I have the VTK User’s Guide but it seems to only describe the basics, and the version I have is for VTK 5.6, is there an up-to-date version of this?

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**Author:** ![lassoan](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lassoan/32/50_2.png) [@lassoan](https://discourse.vtk.org/u/lassoan)\
**Post date:** [June 3, 2020, 4:06pm UTC](https://discourse.vtk.org/t/filter-documentation/3457/2 "2020-06-03T16:06:15Z")

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See a detailed description in this blog post:  
[https://vtk.org/Wiki/VTK/Tutorials/New\_Pipeline](https://vtk.org/Wiki/VTK/Tutorials/New_Pipeline)

I agree that this should be easier to find, probably part of VTK API documentation.

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**Author:** ![Aron\_Helser](https://discourse.vtk.org/user_avatar/discourse.vtk.org/aron_helser/32/14_2.png) [@Aron\_Helser](https://discourse.vtk.org/u/Aron_Helser)\
**Post date:** [June 3, 2020, 5:11pm UTC](https://discourse.vtk.org/t/filter-documentation/3457/3 "2020-06-03T17:11:07Z")

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This blog post series might also be helpful: [https://blog.kitware.com/a-vtk-pipeline-primer-part-1/](https://blog.kitware.com/a-vtk-pipeline-primer-part-1/)

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**Author:** ![SimonFuet](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/s/e95f7d/32.png) [@SimonFuet](https://discourse.vtk.org/u/SimonFuet)\
**Post date:** [June 4, 2020, 7:35am UTC](https://discourse.vtk.org/t/filter-documentation/3457/4 "2020-06-04T07:35:50Z")

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Thank you so much for this! That’s exactly what I was looking for.  
I knew there was stuff in the wiki but i must have missed this one.

Thanks also for the blog post (I didn’t know there was a blog dedicated to VTK)

I wish I’d had this question sooner 😉