Unity 2017.3.0f3升级后Object.Instantiate实例化位置异常求助

Hey there, let's troubleshoot this frustrating instantiation problem you ran into after upgrading from Unity 2017.2.0f3 to 2017.3.0f3! Your code looks straightforward, so let's break down the most likely culprits and fixes:

1. Verify Your Prefab's Transform Settings #

• First, check if your obj prefab has any unexpected local position offsets or is parented to an object in the prefab itself. If the prefab's local Transform isn't set to (0, 0, 0), the instantiated position will be your specified world position plus this local offset—making it seem like the random X value isn't working.
• Also, ensure the prefab doesn't have any locked Transform properties (look for the padlock icon next to Transform values in the Inspector).

2. Confirm Random.Range is Generating Unique Values #

It's possible the random value isn't changing as expected. Add a debug log to verify:

void Inst() { 
    float randomX = Random.Range(-2.1f, 2.1f);
    Debug.Log($"Generated Random X: {randomX}");
    Instantiate(obj, new Vector3(randomX, 6f, 0f), Quaternion.identity); 
}

• If the log shows the same X value every time, check if you're setting a fixed random seed somewhere in your code (like Random.InitState(123)). Unity 2017.3 might have adjusted default seed behavior, so removing any fixed seed calls could fix this.

3. Check for Physics or Parent Object Interference #

• If your obj has a Rigidbody2D component: Make sure Is Kinematic is enabled if you don't want physics to move it. If it's disabled, gravity or collisions with other objects could instantly snap the instantiated object to a fixed position right after spawn.
• Also, check if instantiated objects are automatically being parented to another GameObject (like a spawn container) that has a non-uniform scale or position offset. This would override your specified spawn position. You can modify the Instantiate call to explicitly set no parent:

  Instantiate(obj, new Vector3(randomX, 6f, 0f), Quaternion.identity, null);
  

4. Debug the Instantiated Object's Actual Position #

Sometimes the object's position is correct, but camera settings make it look like it's not. Spawn the object into a variable and log its final world position:

void Inst() { 
    float randomX = Random.Range(-2.1f, 2.1f);
    GameObject spawnedObj = Instantiate(obj, new Vector3(randomX, 6f, 0f), Quaternion.identity);
    Debug.Log($"Spawned Object Position: {spawnedObj.transform.position}");
}

• If the logged position matches your random X value but the view looks wrong, check your camera's settings:
  • For 2D, ensure the camera is set to Orthographic and its Z position is far enough back to see all objects.
  • Verify the camera's Orthographic Size or Position wasn't changed during the Unity version upgrade.

内容的提问来源于stack exchange，提问作者Giovanni