# Seperation plane following closed curve

**URL:** <https://discourse.slicer.org/t/seperation-plane-following-closed-curve/30995>\
**Category:** Support\
**Created:** [August 5, 2023, 11:13am UTC](https://discourse.slicer.org/t/seperation-plane-following-closed-curve/30995 "2023-08-05T11:13:00Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![mohammed\_alshakhas](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/mohammed_alshakhas/32/10025_2.png) [@mohammed\_alshakhas](https://discourse.slicer.org/u/mohammed_alshakhas)\
**Post date:** [August 5, 2023, 11:13am UTC](https://discourse.slicer.org/t/seperation-plane-following-closed-curve/30995/1 "2023-08-05T11:13:00Z")

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I often work with complicated osteotomy geometry that doesn’t follow straight lines or curves.  
I need to experiment with many shapes to see the outcome. it would be so good if I could draw a closed curve and a plane is fitted through it  
thanks

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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:** [August 6, 2023, 11:15pm UTC](https://discourse.slicer.org/t/seperation-plane-following-closed-curve/30995/2 "2023-08-06T23:15:29Z")

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This feature is already available. Your can get the curve coordinate system (plane position, tangent, normal direction) at any curve point. There is also a nice module with a convenient GUI in SlicerVMTK extension: Cross-section analysis module.

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**Author:** ![mohammed\_alshakhas](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/mohammed_alshakhas/32/10025_2.png) [@mohammed\_alshakhas](https://discourse.slicer.org/u/mohammed_alshakhas)\
**Post date:** [August 7, 2023, 4:49am UTC](https://discourse.slicer.org/t/seperation-plane-following-closed-curve/30995/3 "2023-08-07T04:49:54Z")

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Placing curve is not the issue . The request is about having a fitted plane or planes in the closed curve area to perform the cut .

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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:** [August 7, 2023, 7:55am UTC](https://discourse.slicer.org/t/seperation-plane-following-closed-curve/30995/4 "2023-08-07T07:55:59Z")

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I thought you need to fit the plane orthogonally to the curve. Fitting a plane in the curve points is even simpler. Have your tried using [plane fit](https://slicer.readthedocs.io/en/latest/user_guide/modules/markups.html#edit-plane-markups) mode? It draws the plane by fitting it on all the control points that you specify.

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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:** [August 7, 2023, 11:21am UTC](https://discourse.slicer.org/t/seperation-plane-following-closed-curve/30995/5 "2023-08-07T11:21:11Z")

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A post was split to a new topic: [Failed to load nifti file](https://discourse.slicer.org/t/failed-to-load-nifti-file/31023)

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**Author:** ![mohammed\_alshakhas](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/mohammed_alshakhas/32/10025_2.png) [@mohammed\_alshakhas](https://discourse.slicer.org/u/mohammed_alshakhas)\
**Post date:** [August 7, 2023, 5:11pm UTC](https://discourse.slicer.org/t/seperation-plane-following-closed-curve/30995/6 "2023-08-07T17:11:39Z")

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never noticed before, and could not figure out how to use it .  
not clear how to select points and initiate fitting