# vmtkcenterlinegeometry - can't view output file

**URL:** <https://discourse.slicer.org/t/vmtkcenterlinegeometry-cant-view-output-file/21544>\
**Category:** VMTK\
**Tags:** segmentation\
**Created:** [January 20, 2022, 1:55pm UTC](https://discourse.slicer.org/t/vmtkcenterlinegeometry-cant-view-output-file/21544 "2022-01-20T13:55:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![fsneden](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fsneden/32/13546_2.png) [@fsneden](https://discourse.slicer.org/u/fsneden)\
**Post date:** [January 20, 2022, 1:55pm UTC](https://discourse.slicer.org/t/vmtkcenterlinegeometry-cant-view-output-file/21544/1 "2022-01-20T13:55:47Z")

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Hi,

Have used vmtkcenterline geometry to calculate tortuousity of a carotid artery. Output runs fine; the file is written under .vtp extension as in tutorial. However, I want numbers that relate to tortuousity, curvature etc, and no idea how to get these data.

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<div class="post-metadata">

**Author:** ![ramtingh](https://avatars.discourse-cdn.com/v4/letter/r/3ec8ea/32.png) [@ramtingh](https://discourse.slicer.org/u/ramtingh)\
**Post date:** [January 21, 2022, 9:19am UTC](https://discourse.slicer.org/t/vmtkcenterlinegeometry-cant-view-output-file/21544/2 "2022-01-21T09:19:39Z")

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If you want tortuosity, you should use `vmtkbranchgeometry`.  
vmtkcenterlinegeometry produces pointwise curvature and torsion as point data arrays. Easiest way of accessing these is probably through the python/numpy interface.

You can convert it to a .dat file as well which will be a spreadsheet of these values, but unless you have a simple geometry this is going to be difficult to process.