# Using surface cut of segment editor to measure area

**URL:** <https://discourse.slicer.org/t/using-surface-cut-of-segment-editor-to-measure-area/5990>\
**Category:** Support\
**Created:** [March 2, 2019, 3:16am UTC](https://discourse.slicer.org/t/using-surface-cut-of-segment-editor-to-measure-area/5990 "2019-03-02T03:16:56Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![muratmaga](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/muratmaga/32/3622_2.png) [@muratmaga](https://discourse.slicer.org/u/muratmaga)\
**Post date:** [March 2, 2019, 3:16am UTC](https://discourse.slicer.org/t/using-surface-cut-of-segment-editor-to-measure-area/5990/1 "2019-03-02T03:16:56Z")

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I am using surface cut to create freehand polygonial selection. Then, I go an convert this segment to a model to measure its area. However, reported area is twice as large than I expect, since it is also calculating the area behind (I think).

Is there away to configure surface cut to select only the external vertices?

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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:** [March 2, 2019, 4:11am UTC](https://discourse.slicer.org/t/using-surface-cut-of-segment-editor-to-measure-area/5990/2 "2019-03-02T04:11:19Z")

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Yes, if you want to compute area of a 2D polygon then you need to divide the reported 3D surface by 2.

Among the new markups widgets (that is planned to be released early next week) there is a “closed curve” type and for that we will report 2D area (so you won’t need to divide by 2).