Creating an SCNParticleSystem by dragging out the icon from the drawer on the bottom right of Xcode, and into the .scn editor creates an SCNParticleSystem.
Editing its values works fine. Get it doing what I want.
Let's call this ParticleSystem_A.
If I then duplicate this particle system, and rename it to ParticleSystem_B, and change any of its values, all corresponding values in ParticleSystem_A also change, in exactly the same manner.
No matter where I re-order, rename or otherwise manipulate these two particle systems within the editor, changing the values of one always changes the value of the other. It seems impossible to "unlink" them.
Is there a way, in the editor, to unlink them?
There is no way to unshare this in Xcode7 (please file a request). You will have to drag a new particle system instance from the object library to get an independent particle system.