# How to extract both x-, y-, z-coordinates and normalvector at each point of centerline of airwaysegmentation

**URL:** <https://discourse.slicer.org/t/how-to-extract-both-x-y-z-coordinates-and-normalvector-at-each-point-of-centerline-of-airwaysegmentation/35353>\
**Category:** Development\
**Tags:** centerlines\
**Created:** [April 8, 2024, 1:34pm UTC](https://discourse.slicer.org/t/how-to-extract-both-x-y-z-coordinates-and-normalvector-at-each-point-of-centerline-of-airwaysegmentation/35353 "2024-04-08T13:34:02Z")\
**Posts on this page:** 1\
**Showing post:** 8

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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 19, 2024, 1:21pm UTC](https://discourse.slicer.org/t/how-to-extract-both-x-y-z-coordinates-and-normalvector-at-each-point-of-centerline-of-airwaysegmentation/35353/8 "2024-08-19T13:21:59Z")

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> [@mssm](#):
>
> So, if the number of control points is N, the total number of measurement points is 10(N-1)+1 = 10N-9.

If your curve already have many points very close to each other then you can [set the number of points per interpolating segment](https://apidocs.slicer.org/master/classvtkMRMLMarkupsCurveNode.html#ab7e78f2538dae5ea876ae7d0963e376c) to 0.

> [@mssm](#):
>
> By the way, I am very interested in the visualization of normal vectors

This question was also posted and was answered here:

> [@How can I draw normal vectors of a centerline in the 3D slicer?](https://discourse.slicer.org/t/how-can-i-draw-normal-vectors-of-a-centerline-in-the-3d-slicer/37933/5):
>
> Dear Andras Lasso sensei, Thanks a lot. I tried the magic code right away. However, I got the error message as shown in the attached image. Could you please help me again? I also looked into “addCoordinateSystemUpdator”. For some reason, I couldn’t use it in my environment. MacStudio, M2, MacOS Sonoma 14.6.1 Slicer 5.6.2 r32448 / f10cd8c Regards, Masaaki By the way, when application is starting, such messages appears in the python console: Python 3.9.10 (main, Apr 5 2024, 00:33:09) […

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