# Island Effect is deleting other segments (deleting the copies of my original segment)

**URL:** <https://discourse.slicer.org/t/island-effect-is-deleting-other-segments-deleting-the-copies-of-my-original-segment/15945>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [February 11, 2021, 12:40am UTC](https://discourse.slicer.org/t/island-effect-is-deleting-other-segments-deleting-the-copies-of-my-original-segment/15945 "2021-02-11T00:40:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Jezza](https://avatars.discourse-cdn.com/v4/letter/j/dfb087/32.png) [@Jezza](https://discourse.slicer.org/u/Jezza)\
**Post date:** [February 11, 2021, 12:40am UTC](https://discourse.slicer.org/t/island-effect-is-deleting-other-segments-deleting-the-copies-of-my-original-segment/15945/1 "2021-02-11T00:40:36Z")

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Operating system: macOS Catalina 10.15.7  
Slicer version: 4.11 20200930

I managed to duplicate a hollow (vessel wall) version of my model into a solid (blood pool) as described in this post → [How would people extract center line on a hollow model?](https://discourse.slicer.org/t/how-would-people-extract-center-line-on-a-hollow-model/15927)

Now, when I apply the Island Effect "keep largest island’ on either the hollow segment or the solid segment, **the other segment gets deleted aswell!**

I thought that any effects would **only** apply to the **selected** segment, yet it seems that using the “copy” (logical operator) tool gives both segments the same identity and 3DSlicer treats them both as the same segment? Is there a way to make them separate? I do not want my tools to affect both segments simultaneously when I have only selected one of them.

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**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:** [February 11, 2021, 12:53am UTC](https://discourse.slicer.org/t/island-effect-is-deleting-other-segments-deleting-the-copies-of-my-original-segment/15945/2 "2021-02-11T00:53:30Z")

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Copy does not connects segments in any way, if in masking settings you selected “Allow overlap”.

If overlap is allowed (or the segments do not overlap) and modifying a segment still seem to affect another segment then try to do the same in a recent Slicer Preview Release. There were some related fixes since the Slicer-4.11 20200930 release.

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**Author:** ![Jezza](https://avatars.discourse-cdn.com/v4/letter/j/dfb087/32.png) [@Jezza](https://discourse.slicer.org/u/Jezza)\
**Post date:** [February 11, 2021, 7:54pm UTC](https://discourse.slicer.org/t/island-effect-is-deleting-other-segments-deleting-the-copies-of-my-original-segment/15945/3 "2021-02-11T19:54:57Z")

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Thank you, I’ll have a look at that!