# How to subtract overlapping STL surfaces in ParaView?

**URL:** https://discourse.paraview.org/t/how-to-subtract-overlapping-stl-surfaces-in-paraview/16086
**Category:** ParaView Support
**Created:** [January 31, 2025, 1:06am UTC](https://discourse.paraview.org/t/how-to-subtract-overlapping-stl-surfaces-in-paraview/16086 "2025-01-31T01:06:55Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![vbryansm](https://discourse.paraview.org/user_avatar/discourse.paraview.org/vbryansm/32/15794_2.png) [@vbryansm](https://discourse.paraview.org/u/vbryansm)
#### Post date: [January 31, 2025, 1:06am UTC](https://discourse.paraview.org/t/how-to-subtract-overlapping-stl-surfaces-in-paraview/16086/1 "2025-01-31T01:06:55Z")

</div>

I have two STL surfaces (images below). I need to merge them while keeping only the bottom blue surface where they overlap - like removing material from the intersection area. How can I do this?

 ![Captura de tela de 2025-01-30 22-02-10](https://discourse.paraview.org/uploads/default/original/2X/a/a324ba0785ef5aec3974ad50cd8782817a3abd8b.png)  
 ![Print2](https://discourse.paraview.org/uploads/default/original/2X/1/1b84302661ae0bafbc1703b9c3eb3ca5a6d0d42d.png)

---

<div class="post-metadata">

### Author: ![dcthomp](https://discourse.paraview.org/user_avatar/discourse.paraview.org/dcthomp/32/20_2.png) [@dcthomp](https://discourse.paraview.org/u/dcthomp)
#### Post date: [January 31, 2025, 3:04am UTC](https://discourse.paraview.org/t/how-to-subtract-overlapping-stl-surfaces-in-paraview/16086/2 "2025-01-31T03:04:05Z")

</div>

You might check out the response by @Charles_Gueunet on [this thread](https://discourse.paraview.org/t/clipping-based-on-stl-or-obj-file/11735/3).

---

<div class="post-metadata">

### Author: ![vbryansm](https://discourse.paraview.org/user_avatar/discourse.paraview.org/vbryansm/32/15794_2.png) [@vbryansm](https://discourse.paraview.org/u/vbryansm)
#### Post date: [January 31, 2025, 3:26am UTC](https://discourse.paraview.org/t/how-to-subtract-overlapping-stl-surfaces-in-paraview/16086/3 "2025-01-31T03:26:15Z")

</div>

it seems slightly different from what I want, because I have two topographic surfaces. but I’ll take a look in the morning! thanks