# Problems with smoothing the vessel models

**URL:** <https://discourse.slicer.org/t/problems-with-smoothing-the-vessel-models/14125>\
**Category:** Support\
**Created:** [October 18, 2020, 9:12pm UTC](https://discourse.slicer.org/t/problems-with-smoothing-the-vessel-models/14125 "2020-10-18T21:12:08Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Andreas](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Andreas](https://discourse.slicer.org/u/Andreas)\
**Post date:** [October 18, 2020, 9:12pm UTC](https://discourse.slicer.org/t/problems-with-smoothing-the-vessel-models/14125/1 "2020-10-18T21:12:09Z")

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Hello everyone,

I sometimes have vessel models that are very difficult to flatten (see pictures). Is there any way I can tweak the smoothing?

 ![Bild_2020-10-18_195222 (5)](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/4/c/4c4baee64f8f9c3cc5e16d6fef09cad92b4e8751.jpeg)

There is another problem:  
When I have smoothed the vessel and then want to create the hollow body, an opening (hole) is created at the tip of the aneurysm and the shape is greatly changed, that is, it flattens out. How can that be avoided?

 ![Screenshot (4)](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/a/3/a394eb6707a79f5bfb26de1383329710fd12beed.jpeg)  
 ![Screenshot_1 (4)](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/f/ff2af641092e829ea496048abe8642823c965dd9.png)

best regards

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<div class="post-metadata">

**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:** [October 20, 2020, 3:52am UTC](https://discourse.slicer.org/t/problems-with-smoothing-the-vessel-models/14125/2 "2020-10-20T03:52:20Z")

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> [@Andreas](#):
>
> I sometimes have vessel models that are very difficult to flatten (see pictures). Is there any way I can tweak the smoothing?

You can represent vessel with finer resolution by cropping and oversampling the image before segmentation, using Crop volume module (use spacing scale of 0.5 or less).

> [@Andreas](#):
>
> There is another problem:  
> When I have smoothed the vessel and then want to create the hollow body, an opening (hole) is created at the tip of the aneurysm and the shape is greatly changed, that is, it flattens out. How can that be avoided?

Both the flattening and the whole are because there is no space in the segmentation’s binary labelmap for the growth of the aneurysm. The easiest is to leave some space around the vasculature before segmentation, when you crop the input volume. If you already segmented the image then you can adjust the segmentation’s extent by creating a ROI node that encloses the region you need and then use it as “Source geometry” in the “Segmentation geometry” window (that you can bring up by clicking the button next to the master volume selector in Segmentation module).