Parameters are used to communicate between scripting and the controller. They are used to drive transitions and blendtrees for example.
It's important to note that the AnimatorControllerParameters are returned as a copy. The array should be set back into the property when changed.
#pragma strict
class ControllerModifier {
	var controller: UnityEditor.Animations.AnimatorController;
	public function ModifyParameters(parameterIndex: int, newName: String) {
		var parameters: AnimatorControllerParameter[] = controller.parameters;
		parameters[parameterIndex].name = newName;
		controller.parameters = parameters;
	}
}
using UnityEngine; using UnityEditor;
class ControllerModifier { UnityEditor.Animations.AnimatorController controller;
public void ModifyParameters(int parameterIndex, string newName) { AnimatorControllerParameter[] parameters = controller.parameters; parameters[parameterIndex].name = newName; controller.parameters = parameters; } }