# Segment - Area Calculation
**URL:** https://discourse.slicer.org/t/segment-area-calculation/14193
**Category:** Support
**Tags:** segmentation
**Created:** [October 21, 2020, 8:07pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193 "2020-10-21T20:07:26Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@Christos\_Tzerefos](https://discourse.slicer.org/u/Christos_Tzerefos)
#### Post date: [October 21, 2020, 8:07pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/1 "2020-10-21T20:07:26Z")
I am creating with the segment editor a cranial bone 3D shape. I figure out that the surface are exported to the table corresponds to the whole 3d shape. Is there any way to calculate only one of the surfaces of the 3D object (blue arrow) and not the whole surface?
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [October 21, 2020, 8:21pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/2 "2020-10-21T20:21:57Z")
Extracting “one side” of a thin structure is an extremely difficult problem. However, there are many solutions available in Slicer that can be used for particular problems.
For example, you can use Dynamic modeler module to draw a closed curve on one side of the surface. Create a bounding curve on the surface can be automated quite easily, by placing points around the of the boundary - closest points to points far away from the model - in 4-8 directions and connect them using a curve that prefers travelling through high-curvature points.
[ ](https://www.youtube.com/watch?v=nLva95ZF4ko)
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### Author:  [@Christos\_Tzerefos](https://discourse.slicer.org/u/Christos_Tzerefos)
#### Post date: [October 21, 2020, 10:14pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/3 "2020-10-21T22:14:50Z")
Thank you for your response. After I have the model of the upper surface of the initial 3D-model, how I calculate its area in cm^2 ?
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [October 21, 2020, 10:27pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/4 "2020-10-21T22:27:28Z")
You can find surface area of a model in Models module’s Information section.
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### Author:  [@Christos\_Tzerefos](https://discourse.slicer.org/u/Christos_Tzerefos)
#### Post date: [October 22, 2020, 2:24pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/5 "2020-10-22T14:24:18Z")
I managed to create this model\_4 (red color), which is part of the surface of my 3d-object.
The surface area calculated by the software corresponds to only one surface of Model\_4 or it corresponds to both up and down??
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [October 22, 2020, 3:03pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/6 "2020-10-22T15:03:54Z")
You already extracted the “top” part of the closed surface, so you don’t need to divide by 2.
Note that you can skip the Scissors step in Segment Editor and just draw the closed curve directly on the extracted complete skull.
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### Author:  [@Christos\_Tzerefos](https://discourse.slicer.org/u/Christos_Tzerefos)
#### Post date: [October 22, 2020, 3:12pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/7 "2020-10-22T15:12:07Z")
So better draw the closed curve on the skull after i create the skull-model with the threshold?
The volume corresponds to what?
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [October 22, 2020, 4:43pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/8 "2020-10-22T16:43:50Z")
Volume that Models module computes is only applicable for closed surfaces. If you have any opening on the surface then the meaning is undefined.
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### Author:  [@Christos\_Tzerefos](https://discourse.slicer.org/u/Christos_Tzerefos)
#### Post date: [October 23, 2020, 6:34pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/9 "2020-10-23T18:34:20Z")
I have two other questions a little bit irrelevant? Should I create 2 different topics ?
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [October 23, 2020, 6:37pm UTC](https://discourse.slicer.org/t/segment-area-calculation/14193/10 "2020-10-23T18:37:40Z")
Yes, please create a new forum topic for each independent question you would like to discuss.