# Rendering bug with non-simple polygons

**URL:** <https://discourse.slicer.org/t/rendering-bug-with-non-simple-polygons/11848>\
**Category:** Development\
**Created:** [June 3, 2020, 4:34pm UTC](https://discourse.slicer.org/t/rendering-bug-with-non-simple-polygons/11848 "2020-06-03T16:34:34Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![gcsharp](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gcsharp/32/863_2.png) [@gcsharp](https://discourse.slicer.org/u/gcsharp)\
**Post date:** [June 3, 2020, 4:34pm UTC](https://discourse.slicer.org/t/rendering-bug-with-non-simple-polygons/11848/1 "2020-06-03T16:34:34Z")

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I’ve noticed this before, but never had time to investigate. Anyway when an RTSTRUCT has non-simple (self-intersecting) polygons, it does not render correctly in slice view. Should I file a bug report?

![2020-06-03_12-27](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/d/dd3e7daa8d6322ddd5ae9e5e34758d2469c33c0d.png)

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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:** [June 3, 2020, 5:44pm UTC](https://discourse.slicer.org/t/rendering-bug-with-non-simple-polygons/11848/2 "2020-06-03T17:44:45Z")

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We’ll push a fix soon - @Sunderlandkyl is working on it (see [https://github.com/Slicer/Slicer/issues/4959](https://github.com/Slicer/Slicer/issues/4959)).

As a workaround, go to Segmentations module’s Representations section and click “Create” in “binary labelmap”. This will allow using binary labelmap representation for slice intersection display, which works robustly regardless of the complexity of the input.

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**Author:** ![gcsharp](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gcsharp/32/863_2.png) [@gcsharp](https://discourse.slicer.org/u/gcsharp)\
**Post date:** [June 3, 2020, 6:16pm UTC](https://discourse.slicer.org/t/rendering-bug-with-non-simple-polygons/11848/3 "2020-06-03T18:16:20Z")

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Cool. Thanks @Sunderlandkyl !!