Thanks, @estan. Your understanding is correct. I do not want the Origin (or the Spacing) to be incorporated into the 4x4 matrix. I want an additional shift to be incorporated into the 4x4 matrix.
In order to keep this from being a breaking change, we need to have three coordinate systems associated with the images:
- the IJK coords, i.e. what we refer to as Structured Coords in VTK
- the image data coords as we currently understand them, incorporating the Origin and Spacing
- new oriented data coords, which are the current coords multiplied by a new 4x4 matrix
I’ve already given reasons for this approach in my earlier comments, but I can try to give it another go.