# Problems with STL Export when using ThreeCSG

**URL:** <https://discourse.threejs.org/t/problems-with-stl-export-when-using-threecsg/51964>\
**Category:** Questions\
**Tags:** stl-exporter\
**Created:** [May 24, 2023, 11:20am UTC](https://discourse.threejs.org/t/problems-with-stl-export-when-using-threecsg/51964 "2023-05-24T11:20:20Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![L-Wo](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/l-wo/32/36530_2.png) [@L-Wo](https://discourse.threejs.org/u/L-Wo)\
**Post date:** [May 24, 2023, 11:20am UTC](https://discourse.threejs.org/t/problems-with-stl-export-when-using-threecsg/51964/1 "2023-05-24T11:20:21Z")

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Hey,

I am using Three CSG to intersect two letters created with TextGeometry. The result looks great on screen, but when I export to STL, all is not so good.

The model _looks_ fine, but then when I come to slice it in PrusaSlicer (for 3D Printing), it’s clear there is something wrong. I can also load the file into Blender and use the 3D Printing Addon to check the model - it tells me there are 16227 Non-Manifold Edges. If I use the auto-fixing tool, the issue goes away in PrusaSlicer and I can print the object just fine.

So what I need to work out is if there is any way to me to fix this issue before exporting from ThreeJS to avoid needing to take every model into blender. I have tried all kinds of tricks on the internet but nothing has resolved the situation.

I built a minimal reproduction of my code here: [https://codepen.io/L-Wo/pen/ExdreBK](https://codepen.io/L-Wo/pen/ExdreBK) where you can download the resulting STL.

 ![Model in prusaslicer](https://canada1.discourse-cdn.com/flex035/uploads/threejs/original/3X/f/d/fdc1e9e3575f5c96debe827b50c0c3571b8668a1.png)  
 ![Model in prusaslicer after auto-fixing in Blender](https://canada1.discourse-cdn.com/flex035/uploads/threejs/original/3X/2/b/2b51682691efcc6cb65965b1c1d35f4ab23e1826.png)

Thank you so much for any help you can offer!

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<div class="post-metadata">

**Author:** ![Asupkay](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/asupkay/32/39401_2.png) [@Asupkay](https://discourse.threejs.org/u/Asupkay)\
**Post date:** [August 27, 2023, 3:05am UTC](https://discourse.threejs.org/t/problems-with-stl-export-when-using-threecsg/51964/2 "2023-08-27T03:05:05Z")

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Any luck finding a solution to this? I ran into the same issue but pulling it into Blender to run the auto fix doesn’t work for me.