# How to bisect a sketch of a circle?

**URL:** <https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802>\
**Category:** Modeling Questions\
**Created:** [April 16, 2022, 5:52pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802 "2022-04-16T17:52:58Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![Whatsdonisdon](https://avatars.discourse-cdn.com/v4/letter/w/7bcc69/32.png) [@Whatsdonisdon](https://discourse.shapr3d.com/u/Whatsdonisdon)\
**Post date:** [April 16, 2022, 5:52pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802/1 "2022-04-16T17:52:58Z")

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My understanding of Shapr’s sketch tool was that any intersections between sketch lines would create separate segments.

I tried to create a half circle, but found that my circle line wasn’t its own segment.

How can I create a selectable half circle? (Just using a basic shape as an example, I’m really curious how I should be thinking about creating/selecting segments created by intersecting lines)

See this video below:

[![](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/5/9/59f9fa75fac7b41f5d7168f51904a39ad2bd7cb3.jpeg "Shapr3D - select sketch segments that are made from intersections?") ](https://www.youtube.com/watch?v=0FL9uQ53HhU)

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**Author:** ![McD](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/mcd/32/15504_2.png) [@McD](https://discourse.shapr3d.com/u/McD)\
**Post date:** [April 16, 2022, 6:06pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802/2 "2022-04-16T18:06:40Z")

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Use the Trim command to remove the other half.

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**Author:** ![Whatsdonisdon](https://avatars.discourse-cdn.com/v4/letter/w/7bcc69/32.png) [@Whatsdonisdon](https://discourse.shapr3d.com/u/Whatsdonisdon)\
**Post date:** [April 16, 2022, 6:19pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802/3 "2022-04-16T18:19:06Z")

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Thanks @McD!

Are there any options that don’t involve deleting other parts of my geometry / sketch?

Thinking ahead to cases where I am drawing more complex sketches.

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**Author:** ![McD](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/mcd/32/15504_2.png) [@McD](https://discourse.shapr3d.com/u/McD)\
**Post date:** [April 16, 2022, 6:32pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802/4 "2022-04-16T18:32:53Z")

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I typically duplicate a sketch if I want elements out of it. In your case, I might redraw the circle afterward. But then you’ll have a duplicate line where the original half circle remained.

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**Author:** ![Whatsdonisdon](https://avatars.discourse-cdn.com/v4/letter/w/7bcc69/32.png) [@Whatsdonisdon](https://discourse.shapr3d.com/u/Whatsdonisdon)\
**Post date:** [April 16, 2022, 9:02pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802/5 "2022-04-16T21:02:09Z")

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Ah, makes sense! Thank you 🙂

Another noob question I haven’t posted yet - how do you duplicate a sketch? I’ve been working around not knowing how to duplicate any part of a sketch by always projecting the parts I want onto another plane. Sometimes I just want to highlight the parts I need and create a copy but moved elsewhere

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**Author:** ![Whatsdonisdon](https://avatars.discourse-cdn.com/v4/letter/w/7bcc69/32.png) [@Whatsdonisdon](https://discourse.shapr3d.com/u/Whatsdonisdon)\
**Post date:** [April 16, 2022, 9:08pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802/6 "2022-04-16T21:08:22Z")

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Ah just noticed the little [+] on the sketch when in ‘move’! Not sure how to just entirely duplicate a sketch for later use though while keeping it in the same position.

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**Author:** ![McD](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/mcd/32/15504_2.png) [@McD](https://discourse.shapr3d.com/u/McD)\
**Post date:** [April 16, 2022, 9:18pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802/7 "2022-04-16T21:18:29Z")

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DON, this one is easy. Using the pencil, tap and hold for a second or so until you see the little circle form and then drag and select your sketch. Then tap on the little + and then move your sketch to the side. Remember to untapped the + otherwise you’ll keep duplicating it. Give that a try, and let me know if you need further help.

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**Author:** ![McD](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.shapr3d.com/mcd/32/15504_2.png) [@McD](https://discourse.shapr3d.com/u/McD)\
**Post date:** [April 16, 2022, 9:30pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802/8 "2022-04-16T21:30:22Z")

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Another way, is to select your sketch and then add a plane to it, offset in a little bit. And then project your current sketch onto that plane. You can then hide the original plane and work on your new sketch.

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**Author:** ![Whatsdonisdon](https://avatars.discourse-cdn.com/v4/letter/w/7bcc69/32.png) [@Whatsdonisdon](https://discourse.shapr3d.com/u/Whatsdonisdon)\
**Post date:** [April 16, 2022, 10:13pm UTC](https://discourse.shapr3d.com/t/how-to-bisect-a-sketch-of-a-circle/18802/9 "2022-04-16T22:13:15Z")

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Thanks @McD - really appreciate the answers, very helpful.