# VMTK Centerline Computation error
**URL:** https://discourse.slicer.org/t/vmtk-centerline-computation-error/12789
**Category:** Support
**Tags:** vmtk, centerlines, vmtk-centerline
**Created:** [July 30, 2020, 8:40am UTC](https://discourse.slicer.org/t/vmtk-centerline-computation-error/12789 "2020-07-30T08:40:35Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@janneke\_slicer](https://discourse.slicer.org/u/janneke_slicer)
#### Post date: [July 30, 2020, 8:40am UTC](https://discourse.slicer.org/t/vmtk-centerline-computation-error/12789/1 "2020-07-30T08:40:35Z")
Hello,
I want to use VMTK Centerline Computation. However, I get the following error after using the Preview button (it isn’t even possible to use the Start button):
‘local variable ‘vtkvmtkComputationalGeometry’ referenced before assignment’.
I used Slicer 4.10.2 on Windows. I also tried to use the VMTK extension in Slicer 4.11.0, but it says it’s not available for that version.
I’m following the tutorials and can’t find what’s wrong. Can someone please help me?
Thank you.
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [July 30, 2020, 1:16pm UTC](https://discourse.slicer.org/t/vmtk-centerline-computation-error/12789/2 "2020-07-30T13:16:43Z")
Use latest Slicer Preview Release. There is a few-hour gap every morning the new nightly Slicer build is already available but not all the extensions yet. By now SlicerVMTK extension is already built (see [dashboard](http://slicer.cdash.org/index.php?project=SlicerPreview&filtercount=1&showfilters=1&field1=buildname&compare1=63&value1=VMTK)).
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### Author:  [@janneke\_slicer](https://discourse.slicer.org/u/janneke_slicer)
#### Post date: [July 30, 2020, 1:51pm UTC](https://discourse.slicer.org/t/vmtk-centerline-computation-error/12789/3 "2020-07-30T13:51:43Z")
Thank you, it works!
I downloaded the latest Release again and now I can install the VMTK extension.
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### Author:  [@LeeaLee12345](https://discourse.slicer.org/u/LeeaLee12345)
#### Post date: [December 12, 2021, 11:34am UTC](https://discourse.slicer.org/t/vmtk-centerline-computation-error/12789/4 "2021-12-12T11:34:10Z")
Hello, I also have this problem. I have replaced multiple 3D slicer versions and failed. How can I solve it
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [December 14, 2021, 5:42pm UTC](https://discourse.slicer.org/t/vmtk-centerline-computation-error/12789/5 "2021-12-14T17:42:56Z")
You need to use a more recent Slicer version. Since the latest Slicer Stable Release is rather old, I would recommend using the latest Slicer Preview Release.
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### Author:  [@LeeaLee12345](https://discourse.slicer.org/u/LeeaLee12345)
#### Post date: [December 21, 2021, 7:18am UTC](https://discourse.slicer.org/t/vmtk-centerline-computation-error/12789/6 "2021-12-21T07:18:18Z")
Thank you very much! This works！
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [February 27, 2023, 4:52pm UTC](https://discourse.slicer.org/t/vmtk-centerline-computation-error/12789/8 "2023-02-27T16:52:48Z")
A post was split to a new topic: [Unit of radius an length in VMTK centerline computation](https://discourse.slicer.org/t/unit-of-radius-an-length-in-vmtk-centerline-computation/28072)