# The angle beteen two planes

**URL:** <https://discourse.slicer.org/t/the-angle-beteen-two-planes/1404>\
**Category:** Support\
**Tags:** cmf\
**Created:** [November 8, 2017, 1:01pm UTC](https://discourse.slicer.org/t/the-angle-beteen-two-planes/1404 "2017-11-08T13:01:36Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![doc-xie](https://avatars.discourse-cdn.com/v4/letter/d/c77e96/32.png) [@doc-xie](https://discourse.slicer.org/u/doc-xie)\
**Post date:** [November 8, 2017, 1:01pm UTC](https://discourse.slicer.org/t/the-angle-beteen-two-planes/1404/1 "2017-11-08T13:01:36Z")

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Hello,  
In general,there is only one angle between two planes. In the Angle Planes module,after I calculated the angle between two planes,I got three numbers(Pitch,yaw,roll),what is the meaning about the angles respectively?

 ![000](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/4/c/4cb120ff58bbe880031319f697f32886e731c6c0.jpeg)

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**Author:** ![rfenioux](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/rfenioux/32/70007_2.png) [@rfenioux](https://discourse.slicer.org/u/rfenioux)\
**Post date:** [October 27, 2023, 9:11am UTC](https://discourse.slicer.org/t/the-angle-beteen-two-planes/1404/2 "2023-10-27T09:11:28Z")

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The transform between two planes can either be described by :

- one rotation around the intersection line between the planes (= 1 angle + 1 axis vector)
- three rotations around the 3 main directions of the reference frame (x,y,z or in RAS coordinate : RL, AP and SI). These are also known as “Euler angles”

That second representation is used here.