# Draw a specified plane and Angle Planes measure

**URL:** <https://discourse.slicer.org/t/draw-a-specified-plane-and-angle-planes-measure/36063>\
**Category:** Support\
**Created:** [May 10, 2024, 1:27pm UTC](https://discourse.slicer.org/t/draw-a-specified-plane-and-angle-planes-measure/36063 "2024-05-10T13:27:05Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![YLX](https://avatars.discourse-cdn.com/v4/letter/y/c57346/32.png) [@YLX](https://discourse.slicer.org/u/YLX)\
**Post date:** [May 10, 2024, 1:27pm UTC](https://discourse.slicer.org/t/draw-a-specified-plane-and-angle-planes-measure/36063/1 "2024-05-10T13:27:05Z")

</div>

I want to implement in 3D slicer software, given three points to determine a plane, may I ask how this function is implemented? I also want to determine any plane given any point and find the dihedral Angle. I hope you can help me solve such problems. Thank you very much.  
For example, I want to identify a plane at mark F\_1,F\_2,F\_3 in the figure below,the dihedral Angle between the plane and the midsagittal plane is found. The landmarks in the figure below are all specified.

 ![G}87XXGZSK7)(ORC%5~115D](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/8/6/86344b1de6246c88f5283c42144858887d145bc6.jpeg)

Operating system:  
Slicer version:5.4.0  
Expected behavior:  
Actual behavior:

---

<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:** [May 10, 2024, 1:22pm UTC](https://discourse.slicer.org/t/draw-a-specified-plane-and-angle-planes-measure/36063/3 "2024-05-10T13:22:06Z")

</div>

To place a plane by 3 points, you can go to Markups module, add a new plane, and in `Plane settings` section choose `Type` → `Three points`.

You can get the angle between two planes using this [code snippet in the script repository](https://slicer.readthedocs.io/en/latest/developer_guide/script_repository.html#measure-angle-between-two-markup-planes).