# Bug?: Split

**URL:** <https://discourse.mcneel.com/t/bug-split/218972>\
**Category:** Rhino for Mac\
**Tags:** mac\
**Created:** [May 12, 2026, 8:45pm UTC](https://discourse.mcneel.com/t/bug-split/218972 "2026-05-12T20:45:58Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![miano](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/miano/32/762004_2.png) [@miano](https://discourse.mcneel.com/u/miano)\
**Post date:** [May 12, 2026, 8:45pm UTC](https://discourse.mcneel.com/t/bug-split/218972/1 "2026-05-12T20:45:58Z")

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I was rebuilding parts that worked in V7 in V8. In the attachd I have a closed polysrf and a surface. If I split the polysrf with the surface, I get a bad surface.

[Problem Split 2.3dm.zip](https://discourse.mcneel.com/uploads/short-url/xERqJ7lLEx039TDdYb3dgj2ntuM.zip) (125.1 KB)

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**Author:** ![Lagom](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/lagom/32/767418_2.png) [@Lagom](https://discourse.mcneel.com/u/Lagom)\
**Post date:** [May 12, 2026, 9:10pm UTC](https://discourse.mcneel.com/t/bug-split/218972/2 "2026-05-12T21:10:38Z")

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The surface for splitting is bad. It is folded back on itself, and also has a kink. Move the 5 CPs at one end in the z-axis direction to see for yourself.

 ![Skärmbild 2026-05-12 23.07.57](https://global.discourse-cdn.com/mcneel/uploads/default/original/4X/a/6/f/a6f67eb6778d6d55f16423fafefe3d7db81274f7.png)

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<div class="post-metadata">

**Author:** ![miano](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/miano/32/762004_2.png) [@miano](https://discourse.mcneel.com/u/miano)\
**Post date:** [May 12, 2026, 9:23pm UTC](https://discourse.mcneel.com/t/bug-split/218972/3 "2026-05-12T21:23:53Z")

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Then the bug is the sweep2 that created the surface. Let me dig that up.