# Get radius and diameter inside the vessels

**URL:** <https://discourse.slicer.org/t/get-radius-and-diameter-inside-the-vessels/20939>\
**Category:** Support\
**Created:** [December 6, 2021, 10:51pm UTC](https://discourse.slicer.org/t/get-radius-and-diameter-inside-the-vessels/20939 "2021-12-06T22:51:33Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![MAURICIO\_ALBERTO\_LED](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/mauricio_alberto_led/32/12480_2.png) [@MAURICIO\_ALBERTO\_LED](https://discourse.slicer.org/u/MAURICIO_ALBERTO_LED)\
**Post date:** [December 6, 2021, 10:51pm UTC](https://discourse.slicer.org/t/get-radius-and-diameter-inside-the-vessels/20939/1 "2021-12-06T22:51:33Z")

</div>

Operating system: Windows 10  
Slicer version: 4.11.20210226  
Expected behavior: Extract de diameter of the vessel on each point (MarkupsFiducial)  
Actual behavior:Tracebak Error

Hello Good Day  
I am in a project where we are trying determine the ballistic trajectories of bullets inside the brain and the damage. We need to calculate the damage of vessels by measuring the change of their diameter throughout all the vessels length.

I am using SlicerVMTK module and using the the python environment, and pasting the next code:

```auto
c = getNode('CenterlineComputationModel')
points = slicer.util.arrayFromModelPoints(c)
radii = slicer.util.arrayFromModelPointData(c, 'Radius')
for i, radius in enumerate(radii):
print("Point {0}: position={1}, radius={2}".format(i, points[i], radius))

```

Geves me this error:

```auto
Python 3.6.7 (default, Feb 27 2021, 05:09:17) 
[GCC 5.3.1 20160406 (Red Hat 5.3.1-6)] on linux2
>>> c = getNode('CenterlineComputationModel')
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/home/mauricio/Desktop/Slicer-4.11.20210226-linux-amd64/bin/Python/slicer/util.py", line 1312, in getNode
    raise MRMLNodeNotFoundException("could not find nodes in the scene by name or id '%s'" % (pattern if (isinstance(pattern, str)) else ""))
slicer.util.MRMLNodeNotFoundException: could not find nodes in the scene by name or id 'CenterlineComputationModel'
>>> points = slicer.util.arrayFromModelPoints(c)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
NameError: name 'c' is not defined
>>> radii = slicer.util.arrayFromModelPointData(c, 'Radius')
Traceback (most recent call last):
  File "<console>", line 1, in <module>
NameError: name 'c' is not defined
>>> for i, radius in enumerate(radii):
... print("Point {0}: position={1}, radius={2}".format(i, points[i], radius))
...

```

 ![vessel](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/7/3/73622c457e92bb7985f6603b22986b184aaf06a8.png)

Thanks for the help.