# Is it possible to create a new segment from a fiducial point cloud?

**URL:** <https://discourse.slicer.org/t/is-it-possible-to-create-a-new-segment-from-a-fiducial-point-cloud/44408>\
**Category:** Support\
**Created:** [September 9, 2025, 1:15pm UTC](https://discourse.slicer.org/t/is-it-possible-to-create-a-new-segment-from-a-fiducial-point-cloud/44408 "2025-09-09T13:15:03Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![maria\_m](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@maria\_m](https://discourse.slicer.org/u/maria_m)\
**Post date:** [September 9, 2025, 1:15pm UTC](https://discourse.slicer.org/t/is-it-possible-to-create-a-new-segment-from-a-fiducial-point-cloud/44408/1 "2025-09-09T13:15:03Z")

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I am using 3D Slicer for my master’s thesis. My project involves working with 4 slices in the axial plane of a brain MRI. In each slice, I use the segmentation tool to select the cerebral cortex, and then with a Python script, I remove the segment from all other slices, leaving only the 4 selected 2D planes. Using another script, I place around 20 fiducial points around each segment to define its perimeter. I export these points as a CSV file and send them to a colleague. My colleague then returns a point cloud, which I need to visualize again in order to show the brain-shift.

So far, this workflow works, but I am not sure if it is the most efficient approach. I may be using tools in ways they were not originally intended, and I wonder if there might be better methods. Segmentation is inherently a 3D tool, but I am using it in a 2D context, and perhaps simpler representation tools—similar to drawing tools—would be more appropriate since I don’t need a full 3D model.

My main question is whether it is possible to create a new segment to represent the brain’s new position based on the updated fiducial point cloud. I am also open to suggestions for simpler ways to achieve this without relying on segmentation.

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**Author:** ![cpinter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cpinter/32/7995_2.png) [@cpinter](https://discourse.slicer.org/u/cpinter)\
**Post date:** [September 9, 2025, 1:27pm UTC](https://discourse.slicer.org/t/is-it-possible-to-create-a-new-segment-from-a-fiducial-point-cloud/44408/2 "2025-09-09T13:27:56Z")

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Please try the Surface cut effect in the SegmentEditorExtraEffects extension and let us know if it does what you need.