Short question: How can I rotate an object in the shader editor, using vector displacement or other means?
Longer explanation: I have an object which I have instanced many times, each instance has a Track To constraint so each object is pointing to another object - in fact there are three groups of instances, and instances of instances, with three different Track To objects. So far, so good. My problem is that each instanced object now has the same local z rotation, that of the original object, though the local x and y rotations are different in each case, due to the Track To constraints. I would like random z rotations on each instanced object. I cannot z rotate each instance because of the constraints. (Maybe a different constraint would allow this?)
I feel this must be possible using vector displacement, as I know that rotating an object to face the camera is possible with vector displacement, but I have no idea how to do it in this scenario.
If it helps to visualise, the instanced objects are spoke nipples attached to the inner rim of a bicycle wheel. Because of the spoke pattern and position around the wheel, each nipple requires a unique rotation. I want each nipple to be randomly rotated around its z axis, so that they are not all perpendicular to the wheel face as they are at the moment.
Any help would be gratefully received.