# PlaneToWorld: set position of plane to world coordinate system

**URL:** <https://discourse.slicer.org/t/planetoworld-set-position-of-plane-to-world-coordinate-system/25639>\
**Category:** Support\
**Created:** [October 11, 2022, 6:56am UTC](https://discourse.slicer.org/t/planetoworld-set-position-of-plane-to-world-coordinate-system/25639 "2022-10-11T06:56:03Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![jegberink](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jegberink/32/16031_2.png) [@jegberink](https://discourse.slicer.org/u/jegberink)\
**Post date:** [October 11, 2022, 6:56am UTC](https://discourse.slicer.org/t/planetoworld-set-position-of-plane-to-world-coordinate-system/25639/1 "2022-10-11T06:56:03Z")

</div>

Hello Everyone,

I’m trying to create a coordinate system relative to the femur. I have selected three points to create a plane which will now represent the new coordinate system.

Because i work with slicermorphs automatic registration (ALPACA) in order to get a transform from one position to another, i would like my new coordinate system to allign with the world coordinate system so i can measure this position change automatically in the new coordinate system.

From what i gather i can use the example given here to get a transform from plane to the world coordinates: [Creating a new coordinate system - #16 by lassoan](https://discourse.slicer.org/t/creating-a-new-coordinate-system/19446/16)

So i create a plane “P” and insert the code snippet, however nothing happens. I’m sure i’m doing something wrong, some help would be great.

Thank you in advance

---

<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:** [October 19, 2022, 6:28am UTC](https://discourse.slicer.org/t/planetoworld-set-position-of-plane-to-world-coordinate-system/25639/2 "2022-10-19T06:28:49Z")

</div>

Based on [Creating a new coordinate system - #27 by GL1984](https://discourse.slicer.org/t/creating-a-new-coordinate-system/19446/27) it seems you have figured this out (i.e., that you can use the transformation matrix in a transform node and harden that transform - or its inverse - on your node), but if you still have questions then let us know.