Technically slots don't have a rotation at all. Your screenshot shows you have a mesh attachment selected. A mesh only "sort of" has a rotation. A mesh is really just a bunch of vertices (4 in your screenshot). When you use the rotate tool to move all of a mesh's vertices, Spine keeps track of how much you rotated the mesh, but this is only useful as a reference. When you rotate the mesh vertices, they are really just being translated in a circle. If you press Freeze
in the mesh properties, you'll set the mesh rotation to zero (and scale to 1, which is tracked similarly). When you rotate fewer than all the mesh vertices, or you translate the mesh vertices, the mesh rotation doesn't change. You could translate all the vertices in such a way that the mesh appeared that it had been rotated 90 degrees, but it's rotation would stay 0 because it only tracks how much all the vertices have been rotated.
All meshes start as a region attachment. When converted to a mesh attachment, it takes the rotation of the region attachment.
Note that paths, bounding boxes, and clipping attachments work in the same way.
Interestingly, because of your post, I found Spine had a bug where the world rotation for a mesh is wrong. We've now fixed this in 3.7.48-beta! Sorry if that was confusing, it could explain why you are having trouble.
You can try this: select a mesh, ctrl+c
, select another mesh, make sure World
axes are selected (or Local
, if that is what you want), then cltr+v
. This will apply the transform of the first to the second. It should work even if you are using a version of Spine that displays an incorrect world rotation for meshes. Transform copy also works for bones.