Why deactivating objects is so slow?

I’m making an action game with lots of shooting and projectiles, unity version 5.6.
So the problem is, SetActive(false) is being slow. I’m using a pooling system that basically switches objects on and off instead of creating/destroying them, and somehow deactivation is MUCH slower than activation. It’s literally just SetActive(False), nothing else. When same amount of projectiles is ACTIVATED, there’s no lag whatsoever. Only deactivation.

The projectiles are just basic spheres with trigger colliders and rigid bodies.

Here’s a screenshot from the profiler. It’s important to mention that the number of projectiles on scene is dozens or even hundreds, but once again, lag only occurs on deactivation.

Well, if they have a lot of sub-objects, then unity needs to recursively call SetActive for all those sub-objects. Plus you said they were rigidbodies, so that means the physics engine needs to update what it knows about the scene as well when you deactivate them.

I see you’re deactivating 71 objects in a single frame… that seems like a lot. One thing you can do (that I have no idea why it’s not built-in) is to check to make sure they’re not already inactive before calling SetActive.

You might also test if you still have the same problem in a built version. This could be one of those things that has a much higher impact in the editor.