Why Instantiate is so slow?

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 public static void SpawnObject(LevelObject lo, GameObject levelRoot){
 
         //Debug.Log("[" + System.DateTime.Now.ToLongTimeString() + " @ " + System.DateTime.Now.Millisecond +"ms] Spawning object " + Globals.categories[lo.CategoryID].objects[lo.ObjectID].prefabName);
         GameObject go = Instantiate(Globals.EditorObjectCache[Globals.categories[lo.CategoryID].objects[lo.ObjectID].prefabName], new Vector3(lo.posX, lo.posY, lo.posZ),Quaternion.Euler(lo.rotX, lo.rotY, lo.rotZ),levelRoot.transform);
         //Debug.Log("[" + System.DateTime.Now.ToLongTimeString() + " @ " + System.DateTime.Now.Millisecond + "ms] Instantiate done");
         go.transform.localScale = new Vector3(lo.scaleX,lo.scaleY,lo.scaleZ);
         LevelObjectData lod = go.GetComponent<LevelObjectData>();
         lod.setLevelObject(lo);
         
         //TODO: Stop being so humorous in game's code or there will be no humor left for actual game dialogs!
     }

The difference between outputs of the commented debug logs is about 2-3ms and that's instantiate alone. Frankly, the instantiate takes the bulk of time it takes to run this function and unfortunately I haven't been able to optimize it further. The rest of the logic takes 1ms at most. Not very good when said function is a part of custom load routine (for maximum modability, I've developed my own editor and use it instead of Unity's scene editor which is only used for menus) and as such can be called tens of thousands times in a row!

31.05.2018: Updated the function to closely resemble what it does look like now. Yep, definitely Instantiate is to blame, cut other cruft (some functions seemed to be called twice or even thrice), but it still made no difference. Still my level loads in about 1 minute (it has about 10k objects, not counting those that are in the scene to begin with like UIs and managers). Unity definitely needs to improve Instantiate's performance.

Answer 1

Answer by Unified2000 · May 30, 2018 at 09:38 PM

go.transform.rotation=Quaternion.Euler(lo.rotX,lo.rotY,lo.rotZ);

It's probably the loading of assets into video memory that's slow. If an object is referenced in the scene then Unity will load the object into video memory on startup and so a later instantiate should be much faster.

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darkhog · May 31, 2018 at 02:41 PM 0

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$$anonymous$$aybe. But the objects can't be referenced in the scene to begin with as they're dynamically loaded from Resources on game's boot up, then cached, then instantiated from that. I've already shaved the time by half by caching alone, but obviously a $$anonymous$$ute of waiting isn't acceptable for me. Ideally it would be just few seconds.

Unified2000 darkhog · May 31, 2018 at 03:33 PM 0

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I've done something similar in the past. Another thing to consider is mesh colliders. They're horribly slow to generate and so if you have a mesh collider on your object then that will slow instantiate down considerably. I ended up disabling all the mesh colliders on my objects and then after instantiating them I had a script go through the scene and slowly enable the mesh colliders.

Why Instantiate is so slow?

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