3D Array Editmode to Playmode Issue

I’m using a 3D array in an editor script and I want it to save the values so when I hit play I don’t lose my changes. How can I do this?

Never mind the bellow answer doesn’t work. I thought it did but it still won’t work…

Okay I got it to work by removing [System.Serializable] from my script. I removed that and all the serialize fields and it’s working now. Why would those make it not work?