# Problem with Subtract on a revolved surface

**URL:** <https://discourse.shapr3d.com/t/problem-with-subtract-on-a-revolved-surface/1281>\
**Category:** Modeling Questions\
**Created:** [July 14, 2017, 4:13am UTC](https://discourse.shapr3d.com/t/problem-with-subtract-on-a-revolved-surface/1281 "2017-07-14T04:13:55Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![diverdarren](https://avatars.discourse-cdn.com/v4/letter/d/a88e4f/32.png) [@diverdarren](https://discourse.shapr3d.com/u/diverdarren)\
**Post date:** [July 14, 2017, 4:13am UTC](https://discourse.shapr3d.com/t/problem-with-subtract-on-a-revolved-surface/1281/1 "2017-07-14T04:13:55Z")

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Subtract is giving me some crazy results on a revolved surface.

I have created a "ring’ by revolving a circle through 360 degrees. I have then created 2 semi circles which I revolve through 20 degrees- looking to “subtract” them and get a cut out in the ring. when I do this WOW, the result is crazy. Nothing like it should be…

Help, very frustrated.

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**Author:** ![Gabor\_Shapr3D](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/gabor_shapr3d/32/235_2.png) [@Gabor\_Shapr3D](https://discourse.shapr3d.com/u/Gabor_Shapr3D)\
**Post date:** [July 14, 2017, 4:22am UTC](https://discourse.shapr3d.com/t/problem-with-subtract-on-a-revolved-surface/1281/2 "2017-07-14T04:22:21Z")

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Can you share a screenshot? From this, it’s hard to imagine what is happenning.