# How to measure crack size?

**URL:** <https://discourse.slicer.org/t/how-to-measure-crack-size/1018>\
**Category:** Support\
**Created:** [September 6, 2017, 4:56pm UTC](https://discourse.slicer.org/t/how-to-measure-crack-size/1018 "2017-09-06T16:56:36Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![deepmech](https://avatars.discourse-cdn.com/v4/letter/d/e0b2c6/32.png) [@deepmech](https://discourse.slicer.org/u/deepmech)\
**Post date:** [September 6, 2017, 4:56pm UTC](https://discourse.slicer.org/t/how-to-measure-crack-size/1018/1 "2017-09-06T16:56:36Z")

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can we measure the crack dimension in D slicer, how?

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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:** [September 6, 2017, 10:55pm UTC](https://discourse.slicer.org/t/how-to-measure-crack-size/1018/2 "2017-09-06T22:55:16Z")

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Yes. You can measure distances using annotation ruler tool. Select “Ruler” from the annotation toolbar and click on two points in the image. See more information here: [https://www.slicer.org/wiki/Documentation/Nightly/Modules/Annotations](https://www.slicer.org/wiki/Documentation/Nightly/Modules/Annotations)

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**Author:** ![deepmech](https://avatars.discourse-cdn.com/v4/letter/d/e0b2c6/32.png) [@deepmech](https://discourse.slicer.org/u/deepmech)\
**Post date:** [September 7, 2017, 9:37am UTC](https://discourse.slicer.org/t/how-to-measure-crack-size/1018/3 "2017-09-07T09:37:26Z")

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i appreciate the fast and focused answered by you.

thanks sir it helps me a lot.

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**Author:** ![pwang](https://avatars.discourse-cdn.com/v4/letter/p/73ab20/32.png) [@pwang](https://discourse.slicer.org/u/pwang)\
**Post date:** [September 26, 2017, 2:36pm UTC](https://discourse.slicer.org/t/how-to-measure-crack-size/1018/4 "2017-09-26T14:36:31Z")

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Below is the screenshot of my Modify Annotation Properties. Where I can modify the type and choose ruler function?

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/c/3/c3ddfc93656a773473435e283069cae86e7e8a70.png). Thanks.

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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:** [September 26, 2017, 6:22pm UTC](https://discourse.slicer.org/t/how-to-measure-crack-size/1018/5 "2017-09-26T18:22:37Z")

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Select “Ruler” on the place toolbar before you click on the image:

![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/9/29579588a68a7d935a6716f9105636994056e80f.png)

That will create rulers when you click on the image. You cannot change the annotation type after it is placed.

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**Author:** ![pwang](https://avatars.discourse-cdn.com/v4/letter/p/73ab20/32.png) [@pwang](https://discourse.slicer.org/u/pwang)\
**Post date:** [September 26, 2017, 7:43pm UTC](https://discourse.slicer.org/t/how-to-measure-crack-size/1018/6 "2017-09-26T19:43:33Z")

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Great! That is exactly what I want. Thank you so much!