- start a new blender project
- press Z for viewing in wireframe (helps later)
- set the origin of the cube to vertex (-1, -1, -1). Do that by pressing TAB to enter edit mode, A to deselect all, right click vertex (-1, -1, -1), press SHIFTS with the mouse cursor inside the 3D viewer then select Cursor to Selected, then TAB to exit edit mode, CTRLALTSHIFTC and set Origin to 3D Cursor.
- set pivot to the origin (individual origins)
- rotate 45 degrees on X
- add a sphere
- set sphere as child of the cube (CtrlP then selecting Object)
- reset location/origin of sphere (AltG then AltO)
- change transform orientation to local
- select the sphere
- grab sphere (G)
- constraint to Y axis in Local (press Y then Y again)
I expected to have the object move within its local Y axis (rotated in relation to the world coordinates), but unfortunately even pressing Y twice, the Y axis constraint is not being set to the cube's rotated Y (it does show "along local Y" in the status bar).
I did manage once to have it constrained by the proper rotated axis, but I can't seem to understand what I did and couldn't reproduce it again.
Can I get some advice on what I am missing?
MORE INFO It seems to me that when I add the sphere to the cube as a parent, the sphere's rotation is not relative to the cube's. I'd have to rotate the sphere to the same 45 degrees in X. However if I add the sphere the cube as child before I rotate the it, now things work properly. But how do I do it when the cube is already rotated? It would be really not optimal to have to remove rotation every time I wanted to add a child object.