unity-scriptableobjects

Unity ScriptableObject Architecture

Use ScriptableObject assets to store shared data and decouple systems in Unity 6.3 LTS — configuration, event channels, and registries that live as project assets instead of being hard-wired into scenes or singletons. Targets Unity 6.3 LTS (6000.3).

When to use

• Use when you need designer-editable config (weapon stats, level data), to share one value

between unrelated systems, to decouple senders from listeners via event channels, or to build a runtime registry of active objects — without a static/singleton manager.

• Use when the project has *.asset data files backed by : ScriptableObject classes.

When _not_ to use: per-instance runtime state that differs per GameObject (that belongs on a MonoBehaviour) — a ScriptableObject asset is shared by everyone who references it. Saving player progress to disk → save-systems. Plain DTOs that never need to be an asset can just be [System.Serializable] classes.

Core workflow

1. Define the class deriving from ScriptableObject and tag it with [CreateAssetMenu] so

designers can create instances from the Assets menu.

1. Create one or more `.asset` instances in the Project window; each is a shared, named

piece of data referenced by [SerializeField] fields.

1. Reference, don't copy. MonoBehaviours hold a reference to the asset; they all see the

same data, so changing the asset changes every consumer.

1. For decoupling, model signals and shared variables as ScriptableObjects: a

"FloatVariable" the HUD reads and the player writes; an "event channel" the player raises and many systems listen to. Neither side references the other.

1. Reset runtime mutations in OnEnable if the asset is mutated during play, because edits

made in the Editor at runtime persist on the asset (a frequent source of "my values changed after I played").

1. Verify by inspecting the asset values during Play mode and confirming consumers react.

Patterns

1. Config/data asset

using UnityEngine;

[CreateAssetMenu(fileName = "WeaponData", menuName = "Game/Weapon Data", order = 0)]
public class WeaponData : ScriptableObject
{
    public string displayName = "Pistol";
    public int    damage = 10;
    public float  fireRate = 0.25f;
    public GameObject projectilePrefab;
}

public class Weapon : MonoBehaviour
{
    [SerializeField] private WeaponData data;   // assign the shared asset in the Inspector
    private void Fire() => Debug.Log($"{data.displayName} for {data.damage}");
}

2. Shared runtime variable (decouples producer from consumer)

[CreateAssetMenu(menuName = "Game/Float Variable")]
public class FloatVariable : ScriptableObject
{
    [SerializeField] private float initialValue;
    [System.NonSerialized] public float runtimeValue;   // not saved to the asset

    private void OnEnable()
    {
        runtimeValue = initialValue;                    // reset when the asset loads
#if UNITY_EDITOR
        // With Reload Domain off, OnEnable does not run again on Play, so also reset there.
        UnityEditor.EditorApplication.playModeStateChanged -= ResetOnPlay;
        UnityEditor.EditorApplication.playModeStateChanged += ResetOnPlay;
#endif
    }

#if UNITY_EDITOR
    private void OnDisable() => UnityEditor.EditorApplication.playModeStateChanged -= ResetOnPlay;

    private void ResetOnPlay(UnityEditor.PlayModeStateChange change)
    {
        if (change == UnityEditor.PlayModeStateChange.ExitingEditMode) runtimeValue = initialValue;
    }
#endif
}
// Player writes playerHealth.runtimeValue; the HUD reads it — neither references the other.

3. Creating an instance at runtime (not an asset on disk)

// For transient SO data you build in code (e.g. a generated config).
var temp = ScriptableObject.CreateInstance<WeaponData>();
temp.damage = 25;
// ...use temp...  Destroy(temp);   // clean up runtime-created instances

Pitfalls

• Editing an SO at runtime persists in the Editor — values you change during Play stay

changed on the asset after you stop. Keep mutable runtime state in [NonSerialized] fields reset in OnEnable, or it will surprise you. (In a build, asset edits do not persist across launches.)

• Disabled Domain Reload skips your `OnEnable` reset — with Enter Play Mode Options

enabled and Reload Domain off (a Unity 6.3 LTS fast-iteration setting), already-loaded SOs are not re-created when you press Play, so OnEnable never fires and runtimeValue keeps its value from the previous session (non-serialized fields keep their Play-mode values). Also reset on EditorApplication.playModeStateChanged (pattern 2), or from a static [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)] method.

• Expecting per-object state — every reference points to the same asset. If two enemies

need different current HP, store HP on the MonoBehaviour, not the shared SO.

• No frame lifecycle — ScriptableObjects have OnEnable/OnDisable/OnDestroy but no

Update. Don't expect per-frame callbacks.

• Using SOs as a save file — they're authoring assets, not runtime persistence; write

progress with save-systems instead.

• Leaking `CreateInstance` objects — runtime-created instances are not garbage-collected

like plain C# objects; Destroy them when done.

References

• For the event-channel pattern (a GameEvent SO + listeners, type-safe payloads) and

runtime sets/registries (a shared list of active enemies), read references/event-channels.md.

• Primary docs: Unity Manual "ScriptableObject" (/Manual/class-ScriptableObject.html) and

"Enter Play mode with domain reload disabled" (/Manual/domain-reloading.html), plus ScriptReference/ScriptableObject, ScriptReference/CreateAssetMenuAttribute.

Related skills

• unity-csharp-scripting — the MonoBehaviours that consume these assets.
• save-systems — persisting state to disk (what SOs are not for).
• card-game / rpg / survival-crafting — genres that lean on SO-driven data.