# Modifying and/or adding to an imported STL file

**URL:** <https://discourse.shapr3d.com/t/modifying-and-or-adding-to-an-imported-stl-file/28381>\
**Category:** Modeling Questions\
**Created:** [October 12, 2023, 9:12pm UTC](https://discourse.shapr3d.com/t/modifying-and-or-adding-to-an-imported-stl-file/28381 "2023-10-12T21:12:05Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![charliechuck01](https://avatars.discourse-cdn.com/v4/letter/c/b5a626/32.png) [@charliechuck01](https://discourse.shapr3d.com/u/charliechuck01)\
**Post date:** [October 12, 2023, 9:12pm UTC](https://discourse.shapr3d.com/t/modifying-and-or-adding-to-an-imported-stl-file/28381/1 "2023-10-12T21:12:05Z")

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I have an STL model of a stamp head for 3D printing (there is a separate body that screws onto it). I am trying to make different sizes of the head without altering the threaded portion. It seems like Shapr3D will not let me edit the STL mesh, so I’m attempting to add to it. I’ve created a cylinder shape with a bevel that I want to attach to the bottom. When I select my Shapr3D-created object and use Union to select the imported STL mesh, it says “Sheet body cannot be selected.” I thought I’d try to trick it by just putting the two objects close enough that they were intersecting and then exporting an STL (or any other 3D printable file), but every time I get past the file naming screen, Shapr3D just closes my file and returns to it’s start screen. Is there any way to unify the two objects?

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**Author:** ![TheBum](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@TheBum](https://discourse.shapr3d.com/u/TheBum)\
**Post date:** [October 12, 2023, 11:08pm UTC](https://discourse.shapr3d.com/t/modifying-and-or-adding-to-an-imported-stl-file/28381/2 "2023-10-12T23:08:29Z")

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Frankly, you’re better off getting the free version of Fusion 360 and using it to convert the mesh to a solid body. You can then export that body to a STEP file which can then be imported into Shapr3D. It can then be modified. I do that often.

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**Author:** ![Dennis\_L](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@Dennis\_L](https://discourse.shapr3d.com/u/Dennis_L)\
**Post date:** [October 13, 2023, 7:51am UTC](https://discourse.shapr3d.com/t/modifying-and-or-adding-to-an-imported-stl-file/28381/3 "2023-10-13T07:51:19Z")

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Can you explain where i can find this function in fusion please?

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**Author:** ![Eableson](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/eableson/32/10848_2.png) [@Eableson](https://discourse.shapr3d.com/u/Eableson)\
**Post date:** [October 13, 2023, 8:14am UTC](https://discourse.shapr3d.com/t/modifying-and-or-adding-to-an-imported-stl-file/28381/4 "2023-10-13T08:14:23Z")

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Or an alternate option for converting files is: [STL to STEP Converter Online - AnyConv](https://anyconv.com/stl-to-step-converter/)

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**Author:** ![TheBum](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@TheBum](https://discourse.shapr3d.com/u/TheBum)\
**Post date:** [October 14, 2023, 5:56pm UTC](https://discourse.shapr3d.com/t/modifying-and-or-adding-to-an-imported-stl-file/28381/5 "2023-10-14T17:56:07Z")

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![Screenshot 2023-10-14 at 12.52.10 PM](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/b/f/bf2e0f163f894fec11202fce192ab85ba008e38d.jpeg)  
 ![Screenshot 2023-10-14 at 12.52.42 PM](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/6/4/64ab9327f130301bf6caded003d4022653b92512.png)  
 ![Screenshot 2023-10-14 at 12.54.17 PM](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/b/6/b6fffb124ab4786294c49ff2e31bee82de9cb3ea.jpeg)