# Segment Editor: Draw Tube - it makes octagonal prisms instead of smooth cylinders

**URL:** <https://discourse.slicer.org/t/segment-editor-draw-tube-it-makes-octagonal-prisms-instead-of-smooth-cylinders/42223>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [March 19, 2025, 5:18pm UTC](https://discourse.slicer.org/t/segment-editor-draw-tube-it-makes-octagonal-prisms-instead-of-smooth-cylinders/42223 "2025-03-19T17:18:09Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![bobcieri](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bobcieri/32/5633_2.png) [@bobcieri](https://discourse.slicer.org/u/bobcieri)\
**Post date:** [March 19, 2025, 5:18pm UTC](https://discourse.slicer.org/t/segment-editor-draw-tube-it-makes-octagonal-prisms-instead-of-smooth-cylinders/42223/1 "2025-03-19T17:18:09Z")

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I am using the draw tube feature in the segment editor. It is great, except that it is drawing octagonal prisms instead of cylinders/tubes. This is much more apparent when the radius is increased to above 10. Can the number of sides of the polygon be increased to make smoother tubes?

I am running the current Slicer version 5.8.1 on Windows

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/6/d67575381e996353ddea264a26f1ca171969a6c1.jpeg)

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**Author:** ![mau\_igna\_06](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/mau_igna_06/32/9056_2.png) [@mau\_igna\_06](https://discourse.slicer.org/u/mau_igna_06)\
**Post date:** [March 19, 2025, 8:08pm UTC](https://discourse.slicer.org/t/segment-editor-draw-tube-it-makes-octagonal-prisms-instead-of-smooth-cylinders/42223/2 "2025-03-19T20:08:16Z")

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Here is the source:

> <https://github.com/lassoan/SlicerSegmentEditorExtraEffects/blob/784997471e8e4dfede24ab9618519b95be5b4e4d/SegmentEditorDrawTube/SegmentEditorDrawTubeLib/SegmentEditorEffect.py#L525-L528>

You should be able to change the resolution to any you want (only limited by segmentation geometry). Currently the resolution is hard-coded to 8 sides for the tube

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**Author:** ![bobcieri](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bobcieri/32/5633_2.png) [@bobcieri](https://discourse.slicer.org/u/bobcieri)\
**Post date:** [March 19, 2025, 8:19pm UTC](https://discourse.slicer.org/t/segment-editor-draw-tube-it-makes-octagonal-prisms-instead-of-smooth-cylinders/42223/3 "2025-03-19T20:19:31Z")

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Thanks! I will give this a try.