# Ruler does not work properly

**URL:** <https://discourse.slicer.org/t/ruler-does-not-work-properly/14482>\
**Category:** Support\
**Created:** [November 7, 2020, 9:03pm UTC](https://discourse.slicer.org/t/ruler-does-not-work-properly/14482 "2020-11-07T21:03:50Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![iboeth](https://avatars.discourse-cdn.com/v4/letter/i/71c47a/32.png) [@iboeth](https://discourse.slicer.org/u/iboeth)\
**Post date:** [November 7, 2020, 9:03pm UTC](https://discourse.slicer.org/t/ruler-does-not-work-properly/14482/1 "2020-11-07T21:03:51Z")

</div>

Operating system: MacOSCatalina Version 10.15.7  
Slicer version: 14.11.20200930  
Expected behavior:  
Actual behavior: Using the ruler shows no measure of my ROI. What am I doing wrong?

 ![F9BA3F25-CD6C-49A7-B824-2F9303AC35B7](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/8/28fb439a2958c705dca73a84cfc34692957ce9cf.jpeg)

---

<div class="post-metadata">

**Author:** ![manjula](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/manjula/32/80981_2.png) [@manjula](https://discourse.slicer.org/u/manjula)\
**Post date:** [November 7, 2020, 9:26pm UTC](https://discourse.slicer.org/t/ruler-does-not-work-properly/14482/2 "2020-11-07T21:26:54Z")

</div>

I think this is the expected behavior.  
You see the value in the 3D window, not on the slice views.  
Also, you can see the value if you switched to the Annotation module. You will see the length under the value.

---

<div class="post-metadata">

**Author:** ![iboeth](https://avatars.discourse-cdn.com/v4/letter/i/71c47a/32.png) [@iboeth](https://discourse.slicer.org/u/iboeth)\
**Post date:** [November 7, 2020, 9:37pm UTC](https://discourse.slicer.org/t/ruler-does-not-work-properly/14482/3 "2020-11-07T21:37:04Z")

</div>

Oh, I see! Thank you very much.  
Could you at least please explain how to switch into Annotation module?

---

<div class="post-metadata">

**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:** [November 7, 2020, 9:42pm UTC](https://discourse.slicer.org/t/ruler-does-not-work-properly/14482/4 "2020-11-07T21:42:23Z")

</div>

I would recommend to use the much improved “Line” markups instead of the legacy annotation rulers.

---

<div class="post-metadata">

**Author:** ![iboeth](https://avatars.discourse-cdn.com/v4/letter/i/71c47a/32.png) [@iboeth](https://discourse.slicer.org/u/iboeth)\
**Post date:** [November 7, 2020, 9:45pm UTC](https://discourse.slicer.org/t/ruler-does-not-work-properly/14482/5 "2020-11-07T21:45:32Z")

</div>

thank you - this is great!!