# Making circles and arcs concentric

**URL:** <https://discourse.shapr3d.com/t/making-circles-and-arcs-concentric/13075>\
**Category:** Modeling Questions\
**Created:** [May 30, 2021, 1:35pm UTC](https://discourse.shapr3d.com/t/making-circles-and-arcs-concentric/13075 "2021-05-30T13:35:14Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ajitgeorge12](https://avatars.discourse-cdn.com/v4/letter/a/4bbf92/32.png) [@ajitgeorge12](https://discourse.shapr3d.com/u/ajitgeorge12)\
**Post date:** [May 30, 2021, 1:35pm UTC](https://discourse.shapr3d.com/t/making-circles-and-arcs-concentric/13075/1 "2021-05-30T13:35:14Z")

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Hi,

I drew about 8 concentric circles. I selected them all and used the Concentric constraint.

Later I cut arcs in these circles and added radial and other lines to them.

When I zoom in to a resolution of 0.01 mm, I find that the centres of these arcs is no longer concentric. Is there anyway I can make make these arcs concentric again without having to delete the radial / other lines that connect these arcs?

The image of the centres in the zoomed figure is pasted below:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/4/4623034cdbadfd3d5d53f808fd9ca413927302d0.png)

An image of the arcs and connecting lines is below:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/2X/f/f505ff6cf82184a3bf5d656ec8461493c9ad78e9.png)

Thanks,  
Ajit

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**Author:** ![TheBum](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@TheBum](https://discourse.shapr3d.com/u/TheBum)\
**Post date:** [June 9, 2021, 4:04pm UTC](https://discourse.shapr3d.com/t/making-circles-and-arcs-concentric/13075/2 "2021-06-09T16:04:39Z")

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Did you try using the Concentric constraint? You have to select only two points for it to be available, I believe. Just keep selecting pairs of points until everything is concentric.

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**Author:** ![bbuxton](https://avatars.discourse-cdn.com/v4/letter/b/b9e5f3/32.png) [@bbuxton](https://discourse.shapr3d.com/u/bbuxton)\
**Post date:** [August 21, 2022, 1:13am UTC](https://discourse.shapr3d.com/t/making-circles-and-arcs-concentric/13075/3 "2022-08-21T01:13:21Z")

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At times drawing in Shapr3d is incredibly clumsy. ‘Arc from centre’ is a glaring omission, yes you can two points and then locate the centre but that is not always comfortable. Please put the option in there. Driven dimensions are important too, I want to set a length that is the sum of two existing dimensions. There are lots of missing features like this that make sketching very slow and unnecessarily complicated.