# STL file import, edit and volume measurment

**URL:** <https://discourse.slicer.org/t/stl-file-import-edit-and-volume-measurment/17377>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [April 28, 2021, 11:05pm UTC](https://discourse.slicer.org/t/stl-file-import-edit-and-volume-measurment/17377 "2021-04-28T23:05:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ashkansh](https://avatars.discourse-cdn.com/v4/letter/a/54ee81/32.png) [@ashkansh](https://discourse.slicer.org/u/ashkansh)\
**Post date:** [April 28, 2021, 11:05pm UTC](https://discourse.slicer.org/t/stl-file-import-edit-and-volume-measurment/17377/1 "2021-04-28T23:05:15Z")

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Hi all,

I imported a .STL file as segmentation and I tried to cut a piece of the part and measure the volume of the rest.  
When I tried to use segment editor to use scissors, I had to define the volume as I defined it in the Specify Geometry section. Then I tried to use the scissor and faced this:

“Editing requires binary labelmap master representation, but currently the master representation is Closed surface. Changing the master representation requires conversion. Some details may be lost during conversion process.  
Change master representation to binary labelmap?”

when I accepted this the resulted shape kind of shrunk and I didn’t want this. Does anyone know how the segmentation could be as close as possible to the original .STL file I imported during the editing?

I appreciate your responses in advance.

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [September 7, 2021, 6:59pm UTC](https://discourse.slicer.org/t/stl-file-import-edit-and-volume-measurment/17377/2 "2021-09-07T18:59:23Z")

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You can either [specify a sufficiently accurate labelmap geometry](https://slicer.readthedocs.io/en/latest/user_guide/modules/segmenteditor.html#segmentation-is-not-accurate-enough) or edit the surface mesh using Dynamic modeler module (you can do simple plane cuts) or using Combine models module (in Sandbox extensions; you can modify the mesh by subtracting or intersecting with another mesh of arbitrary shape).