# Extrusion in imported mesh body

**URL:** <https://discourse.shapr3d.com/t/extrusion-in-imported-mesh-body/17204>\
**Category:** Modeling Questions\
**Created:** [February 3, 2022, 7:37pm UTC](https://discourse.shapr3d.com/t/extrusion-in-imported-mesh-body/17204 "2022-02-03T19:37:56Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![davidtheITguy](https://avatars.discourse-cdn.com/v4/letter/d/cdc98d/32.png) [@davidtheITguy](https://discourse.shapr3d.com/u/davidtheITguy)\
**Post date:** [February 3, 2022, 7:37pm UTC](https://discourse.shapr3d.com/t/extrusion-in-imported-mesh-body/17204/1 "2022-02-03T19:37:56Z")

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Hi,

I have an imported STL with mesh bodies. I am trying to blow a hole through one of the mesh body side faces. I’m using extrusion but I only get an addition to the mesh (cylinder) and not a subtraction of what I have sketched. Boolean operations also do nothing.

I’ve done this before successfully but it’s been some time (I.e. a few versions back).

I know that there are limitations on imported mesh objects but this 100% worked before (I’m staring at a printed box I imported and then manipulated).

What a I doing wrong? Thanks for the help

David

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<div class="post-metadata">

**Author:** ![davidtheITguy](https://avatars.discourse-cdn.com/v4/letter/d/cdc98d/32.png) [@davidtheITguy](https://discourse.shapr3d.com/u/davidtheITguy)\
**Post date:** [February 3, 2022, 7:42pm UTC](https://discourse.shapr3d.com/t/extrusion-in-imported-mesh-body/17204/2 "2022-02-03T19:42:50Z")

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Fixed it myself. The Boolean subtract operation is the way to go provided you do not select to keep originals…