AI character prefab behaves differently when instantiated at runtime vs placed in editor

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1

I’m facing an unusual problem with my AI character. When I add the prefab directly to the scene using the editor, it runs smoothly. However, when I try to create the same prefab during the game, the AI misbehaves.

The main issue arises with the ThirdPersonCharacter script linked to my AI. The character stays stuck in the idle animation and won’t transition to walking. I pinpointed the problem to the “CheckGroundStatus()” function where this line causes a failure:

animatorController.applyRootMotion = false;

Instead of transitioning to the walking animation, the character slides along the ground as it moves to its target. It seems like the ground detection is malfunctioning, but I can’t understand why the prefab would act differently when it’s added via the editor versus during runtime.

I’m using the standard AI setup provided by Unity. Has anyone experienced something like this? What might lead to such different behavior between editor placement and runtime instantiation?

2

This sounds like a timing issue with component initialization. When you spawn prefabs at runtime, execution order changes compared to editor placement. Your CheckGroundStatus function might run before components are fully ready. I had the same problem - my NavMeshAgent wasn’t ready when my animation controller tried accessing it. Try adding a brief delay or use Start() instead of Awake() for ground checking. You could also use a coroutine that waits a frame before checking ground status. Another possibility: your NavMeshAgent spawns at a slightly different position relative to the ground, so the raycast in CheckGroundStatus misses. Add some debug logging to compare ground detection between editor-placed and runtime-spawned versions.