# Render the covered object

**URL:** <https://discourse.vtk.org/t/render-the-covered-object/8457>\
**Category:** Development\
**Tags:** proposal\
**Created:** [May 10, 2022, 7:24am UTC](https://discourse.vtk.org/t/render-the-covered-object/8457 "2022-05-10T07:24:06Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Ren](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/r/ed655f/32.png) [@Ren](https://discourse.vtk.org/u/Ren)\
**Post date:** [May 10, 2022, 7:24am UTC](https://discourse.vtk.org/t/render-the-covered-object/8457/1 "2022-05-10T07:24:06Z")

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Hello, everyone.  
I have two objects to render, one is covered by the other, how to draw the covered object in VTK?  
In OpenGL, I can set the GL\_DEPTH\_TEST, but I can’t find the api in VTK, thanks.

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**Author:** ![Ren](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/r/ed655f/32.png) [@Ren](https://discourse.vtk.org/u/Ren)\
**Post date:** [May 19, 2022, 7:39am UTC](https://discourse.vtk.org/t/render-the-covered-object/8457/2 "2022-05-19T07:39:00Z")

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![无标题](https://discourse.vtk.org/uploads/default/original/2X/b/b939255ed566b359a52e44fedeb1add8d8bdb318.png)  
The red line is back of the green line, but we can see the red line

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**Author:** ![Ren](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/r/ed655f/32.png) [@Ren](https://discourse.vtk.org/u/Ren)\
**Post date:** [June 16, 2022, 9:28am UTC](https://discourse.vtk.org/t/render-the-covered-object/8457/3 "2022-06-16T09:28:50Z")

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Who knows?

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**Author:** ![mau\_igna\_06](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mau_igna_06/32/8064_2.png) [@mau\_igna\_06](https://discourse.vtk.org/u/mau_igna_06)\
**Post date:** [June 16, 2022, 4:30pm UTC](https://discourse.vtk.org/t/render-the-covered-object/8457/4 "2022-06-16T16:30:47Z")

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Maybe set 50% opacity as a property of the actor or the mapper?