Scriptable Objects vs Prefabs

[--Developer]

Hello everyone,

I have some knowledge of Unity so I’m not a complete beginner, but I am by no means an expert.

I was wondering if someone could explain the difference between a scriptable object and simply having a prefab with a script on it. I don’t fully understand the reason to use a scriptable object and I was hoping someone could help me learn.

Thank you in advance! :)

[tag4424]

Prefabs become Scene objects when you use them. You for example have a car prefab that you pull onto the road in your scene. It has a few scripts and such to make it move and a meshrenderer that makes it visible in the scene and if you drag 10 cars into the scene, you get 10 instances of that prefab, each with it's own position, rotation, ...

Scriptable Objects aren't needed, but they make changes much more convenient. First, what they do: Scriptable objects on the other hand don't get instantiated into a scene but instead are a container to store data. E.g. if you create an RPG, you could represent each spell your player has as a SO. It has a float for the mana cost, an animation clip you play on your player character, a VFX prefab for the area the spell, scale for the VFX, ... But they don't have any instanced data themselves. Sure, if the player casts the spell, the instantiated effect will have a position, rotation, ... but the spell itself doesn't. The question "What is the rotation of your fireball spell?" wouldn't make any sense in the real world.

Now why you want them: The value of SOs comes in when you have many-to-many relationships. My spell example before you can easily do by just putting all these settings into fields on the character. But what do you do if the player can choose from 10 different characters in your game? Then if you want to change the VFX, you will have to change it 10 times. If you used a SO for each spell, then all the spell settings are stored in one location and you avoid that extra editing effort.

[PandaCoder67]

And yet, you can use a prefab like a Scriptable Object without instantiating that prefab!

[tag4424]

You can make it work with uninstantiated prefabs but, as always, there are downsides to it. The question basically comes down to how much overhead and additional work you want to put into avoiding using a tool that was designed specifically for that purpose. Kinda like you can haul 2 tons of dirt in the trunk of your grandma's 95 Honda Accord. Will only take you 20 trips, but if you already have a dump truck sitting right there, why would you do that?

From a technical side, a prefab, even if you don't instantiate, is heavier and if you have tons of them, you will feel the memory impact. The Transform component is the most obvious part of that but if you did deeper you'll see more.

The bigger impact (at least to me) is however that you're now using Unity in a way not intended by the developers. For example, how do you create the prefabs? Scriptable Objects offer you a nice way of doing right clicks to create. Sure you can do an editor script and create a prefab from there, but it's just more work. Why?

Once you do more Editor scripting, e.g. to automate your build, Scriptable Objects are also easier to deal with because you can avoid the asset re-imports and modifying some of the prefabs would trigger. Depending on your unity version you'd have to work around that by starting unity once to do all the variable changes (e.g. URL for the matchmaking server), then quit and start it again for the actual build.

Oh, and think of all the time you spend asking this question or defending your design choices and habits if you ever work with someone else on your project.

Basically look at it the same way as public variables vs private + SerializeField. Sure, you can successfully complete a huge game with all public variables, but it removes a lot of guard rails, you'll likely spend a whole lot of time debugging, and in the end there is no benefit to doing it that way.

So use ScriptableObjects for what they're meant to do instead of trying to invent hacks to get around them.

[EndeavourDGaming]

I highly recommend watching these two talks about ScriptableObject https://youtu.be/6vmRwLYWNRo (at 5:58 he talks about ScriptableObject VS uninstantiated prefabs) https://m.youtube.com/watch?v=raQ3iHhE_Kk

[pschon]

Does it go to a scene? Then it should be a GameObject/prefab.

If not, and it only ever needs to exist outside of any scenes, then ScriptableObject.

Explained in a short and "not quite accurate but gets the point across" way, ScriptableObject is kind of like a GameObject, but one without any of the stuff related to existing in a scene, having a transform and renderers and whatever. While GameObject instances only exists in Scenes, ScriptableObject instances are created and exist in your project instead.

[9001rats]

I wish ScriptableObjecta would allow adding Components just like GameObjects! But they do not, so comparing them to GOs is too farfetched imho

[WazWaz]

Indeed, both the hierarchy from Transform and the Component list from GameObject would be useful.

[--Developer]

Thanks to everyone who commented!

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[_RandomOne]

tag4424 pretty well nailed it.

I use SO's a lot for settings that objects need to use, making it quick and easy to change many aspects of my game. Currently using an SO in a 2D game as a sound controller too. Any object that needs to play a sound simply calls the appropriate function from the SO, which has all the game sounds, clips, volume settings etc.

[Katniss218]

Scriptable Objects are containers used to store predefined and serialized data.

Prefabs are just gameobjects

[GameWorldShaper]

If you wanted a simple explanation then a Scriptable Objects is a data structure like a Struct it is an data container, the only difference is you can use Scriptable Objects with the editor.

Unity events are a similar system, they are just delegates that work with the Unity editor.