# How can I draw normal vectors of a centerline in the 3D slicer?

**URL:** https://discourse.slicer.org/t/how-can-i-draw-normal-vectors-of-a-centerline-in-the-3d-slicer/37933
**Category:** Support
**Tags:** centerlines, vmtk-centerline
**Created:** [August 18, 2024, 5:11pm UTC](https://discourse.slicer.org/t/how-can-i-draw-normal-vectors-of-a-centerline-in-the-3d-slicer/37933 "2024-08-18T17:11:32Z")
**Posts on this page:** 1
**Showing post:** 5

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### Author: ![mssm](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/mssm/32/76622_2.png) [@mssm](https://discourse.slicer.org/u/mssm)
#### Post date: [August 19, 2024, 8:38am UTC](https://discourse.slicer.org/t/how-can-i-draw-normal-vectors-of-a-centerline-in-the-3d-slicer/37933/5 "2024-08-19T08:38:51Z")

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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)  
[Clang 14.0.6 ([https://github.com/tru/llvm-release-build](https://github.com/tru/llvm-release-build) 686807a176470032c208f2 on darwin

> > >

Failed to load vtkSlicerCrossSectionAnalysisModuleLogicPython: No module named vtkSlicerShapeModuleMRMLPython  
Failed to load vtkSlicerStenosisMeasurement3DModuleLogicPython: No module named vtkSlicerShapeModuleMRMLPython  
[Qt] Error(s):  
[Qt] CLI executable: /Applications/Slicer.app/Contents/Extensions-32448/SlicerVMTK/lib/Slicer-5.6/qt-loadable-modules/vtkvmtk.py  
[Qt] The process failed to start. Either the invoked program is missing, or you may have insufficient permissions to invoke the program.  
[Qt] Fail to instantiate module “vtkvmtk”  
[Qt] The following modules failed to be instantiated:  
[Qt] vtkvmtk  
[Qt] Populating font family aliases took 92 ms. Replace uses of missing font family “.AppleSystemUIFont” with one that exists to avoid this cost.  
[FD] 2024-08-19 17:49:10.513 Slicer[69837:4024985] NSEventModifierFlagFunction specified to -setKeyEquivalentModifierMask: for item \<NSMenuItem: 0x600007cd9570 PopClipを表示, ke=‘Command-F15’\>, but is only supported for system-provided menu items; will not be used

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/7/6/76bbf89393e57e02fe5efc08f118dda476ebf3e2.jpeg)

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