Hi Fluvio,
Thank you very much for your reply!
- I’ve used the same method as you for translating the centroid to the origin, but I didn’t know there was a way to use the arc-length to calculate the rotation! This is good to know. I am quite an inexperienced coder (and by that I mean 0 experience, haha), but this seems very useful!
- I have not tried this method, but it may not be ideal, as it is crucial in my project that the three axes are orthogonal to one another.
To explain my project further, I have attached images below.
The model seen in the 3D view is the bone block of interest, and the blue model is the neutral condition while the red model is the condition (models are overlaid on top of each other). While they appear to be registered, they are not, as the difference in rotation we are looking for is expected to be ≤ 1˚. In the images attached, the centroids of both the neutral and the condition bone block have been moved to the origin.
Our objective is to find the amount of translation and rotation of the condition bone block relative to the neutral bone block.
In method #1 which you have explained in your reply, did you move the centroids of both models to the origin? or just the reference model?
Further, it would be awesome if you could provide me with some guidance as to where I could learn the coding for using the arc length to calculate the rotation.
Thank you!
Michele
P.S. Please note that the red axes in both images were added to a screenshot rather than created in 3d slicer. The top image represents the global coordinate system, and the second image is what I was hoping for the local coordinate system to look like.