# STL opening in Prusa slicer appears with size incorrect

**URL:** <https://discourse.shapr3d.com/t/stl-opening-in-prusa-slicer-appears-with-size-incorrect/28724>\
**Category:** Modeling Questions\
**Created:** [November 2, 2023, 4:30pm UTC](https://discourse.shapr3d.com/t/stl-opening-in-prusa-slicer-appears-with-size-incorrect/28724 "2023-11-02T16:30:46Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![nelsonmleite](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@nelsonmleite](https://discourse.shapr3d.com/u/nelsonmleite)\
**Post date:** [November 2, 2023, 4:30pm UTC](https://discourse.shapr3d.com/t/stl-opening-in-prusa-slicer-appears-with-size-incorrect/28724/1 "2023-11-02T16:30:46Z")

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I created in an iPad’s sharpr3d stl archives, but when it goes to Prusa slicer there are different dimensions. I put the project in centimeters, but in Prusa appears in millimeters. I need correct the difference or it is a bug? I thought that the difference was because I used a Mac OS Shapr3D and a Prusa slicer even to a Mac OS computer. Then, I changed to win 11 computer and repeated the same problem- centimeters in stl from Sharpr 3D from my iPad are transformed in millimeter.

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**Author:** ![TigerMike](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tigermike/32/32650_2.png) [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)\
**Post date:** [November 2, 2023, 6:12pm UTC](https://discourse.shapr3d.com/t/stl-opening-in-prusa-slicer-appears-with-size-incorrect/28724/2 "2023-11-02T18:12:00Z")

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It’s not a bug. Export your STL from Shapr3D in millimeters, not centimeters.

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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:** [November 2, 2023, 6:17pm UTC](https://discourse.shapr3d.com/t/stl-opening-in-prusa-slicer-appears-with-size-incorrect/28724/3 "2023-11-02T18:17:16Z")

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Or export as 3mf, which preserves units.

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**Author:** ![TigerMike](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tigermike/32/32650_2.png) [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)\
**Post date:** [November 2, 2023, 6:46pm UTC](https://discourse.shapr3d.com/t/stl-opening-in-prusa-slicer-appears-with-size-incorrect/28724/4 "2023-11-02T18:46:09Z")

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I agree that 3mf is better for preserving units and such however I prefer to export as STL in millimeters for 3D printing. I too use Prusaslicer and the problem I have is that Prusaslicer saves project files in 3mf format. Once saved, I cannot determine which 3mf files are project files or STL files.

I’m guessing that @nelsonmleite 's problem is the fact his STL was exported in METRIC, be it centimeters or meters for that matter, I’ll guess that Prusaslicer automatically sees it in millimeters which would make his model 1/10 the size sitting on the printer bed. Again, my guess.

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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:** [November 2, 2023, 6:55pm UTC](https://discourse.shapr3d.com/t/stl-opening-in-prusa-slicer-appears-with-size-incorrect/28724/5 "2023-11-02T18:55:03Z")

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Simplify3D sees STLs in mm too unless the dimensions are really small, in which case it gives you some conversion options. Simplify3D saves projects in .factory files, which contain the printer profiles as well as the model parameters.

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**Author:** ![TigerMike](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/tigermike/32/32650_2.png) [@TigerMike](https://discourse.shapr3d.com/u/TigerMike)\
**Post date:** [November 2, 2023, 7:26pm UTC](https://discourse.shapr3d.com/t/stl-opening-in-prusa-slicer-appears-with-size-incorrect/28724/6 "2023-11-02T19:26:22Z")

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I too have and use Simplify3D for 3D printing on my Lulzbot Taz6. A lot of nice features like viewing gcode files whether or not they were sliced in Simplify3D or not.  
My other reason for saving STL files in STL format is that I can view them on my iMac via Finder. It’s not all that important but it’s nice to have.

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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:** [November 3, 2023, 5:17am UTC](https://discourse.shapr3d.com/t/stl-opening-in-prusa-slicer-appears-with-size-incorrect/28724/7 "2023-11-03T05:17:48Z")

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One advantage to letting a 3MF (or even STL) file open in Simplify3D is I can get a sense of scale. I can’t tell how big the object is in the Preview app rendition.