# Unable to create a B-Spline Registration

**URL:** <https://discourse.slicer.org/t/unable-to-create-a-b-spline-registration/41764>\
**Category:** Support\
**Created:** [February 19, 2025, 12:59am UTC](https://discourse.slicer.org/t/unable-to-create-a-b-spline-registration/41764 "2025-02-19T00:59:01Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ABirch](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@ABirch](https://discourse.slicer.org/u/ABirch)\
**Post date:** [February 19, 2025, 12:59am UTC](https://discourse.slicer.org/t/unable-to-create-a-b-spline-registration/41764/1 "2025-02-19T00:59:01Z")

</div>

Greetings, I am having some trouble creating a B-spline registration for 2 lung CTs, one with inhalation (0%) and one with exhalation (50%). The 50% image should be the fixed image. When doing a B-spline registration the following output image (I also put the 0%, 50% and settings):

Output Image:

 ![Screen Shot 2025-02-18 at 12.47.49 PM](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/9/d97a993ef1d61ca45303a3738629e2cad976bfdc.png)

0%:

 ![Screen Shot 2025-02-18 at 12.48.09 PM](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/b/2be8330ea2eec2efae1db3cb09490252aec6d545.png)

50%:

 ![Screen Shot 2025-02-18 at 12.48.30 PM](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/5/9/594c9f6e2f889d4eeba7e5ecd73ae9df568e0699.png)

Settings:

 ![Screen Shot 2025-02-18 at 12.48.48 PM](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/b/3/b3d89870c1f029f26a74dcf899fbb3666621af0e.png)

The output image looks basically the same as the 0% and I don’t believe anything is registered. Is there anything I am doing incorrectly?