# How to customize Z-buffer with several Polydata

**URL:** https://discourse.vtk.org/t/how-to-customize-z-buffer-with-several-polydata/3129
**Category:** Support
**Created:** [April 23, 2020, 9:42am UTC](https://discourse.vtk.org/t/how-to-customize-z-buffer-with-several-polydata/3129 "2020-04-23T09:42:54Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![BotellaA](https://discourse.vtk.org/user_avatar/discourse.vtk.org/botellaa/32/1243_2.png) [@BotellaA](https://discourse.vtk.org/u/BotellaA)
#### Post date: [April 23, 2020, 9:42am UTC](https://discourse.vtk.org/t/how-to-customize-z-buffer-with-several-polydata/3129/1 "2020-04-23T09:42:54Z")

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I have several Polydata representing surfaces in the same camera. They are in contact at their boundaries. I can see the polydata mesh that is supposed to be hidden. I tried to change the `ClippingRange` but it did not change the result.

 ![zbuffer](https://discourse.vtk.org/uploads/default/original/2X/0/0e505ecb76c29ca60955fba719e24428fccf9492.png)

Do you know why?  
Thanks for your help

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### Author: ![Sebastien\_Jourdain](https://discourse.vtk.org/user_avatar/discourse.vtk.org/sebastien_jourdain/32/100_2.png) [@Sebastien\_Jourdain](https://discourse.vtk.org/u/Sebastien_Jourdain)
#### Post date: [April 23, 2020, 10:07am UTC](https://discourse.vtk.org/t/how-to-customize-z-buffer-with-several-polydata/3129/2 "2020-04-23T10:07:02Z")

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You need to play with the line offset on the mapper (static methods).

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### Author: ![BotellaA](https://discourse.vtk.org/user_avatar/discourse.vtk.org/botellaa/32/1243_2.png) [@BotellaA](https://discourse.vtk.org/u/BotellaA)
#### Post date: [April 23, 2020, 3:32pm UTC](https://discourse.vtk.org/t/how-to-customize-z-buffer-with-several-polydata/3129/3 "2020-04-23T15:32:39Z")

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Thanks!

I called `SetResolveCoincidentTopologyToPolygonOffset()` but it does not seem to be enough. From your previous message, I think I have to call `SetResolveCoincidentTopologyLineOffsetParameters()` too but I do not understand what the parameters `factor` and `units` represent.