How to fix the platforms?

Questions & Answers
1

I have a problem with the platforms. I’ve made a trigger object and when it passes the ball that object,I made to create a new platform but two new platforms will be create and when I pass the second platform then four new platforms will be create.How to fix this, need to create one platform but create more?sorry bad english.

108384-untitled.jpg
108384-untitled.jpg1366×728 227 KB

108387-fhghdf.png
108387-fhghdf.png1000×476 510 KB

This is the code for new platforms

public Transform roadprefab;
void OnTriggerEnter(Collider other)
{
	Instantiate(roadprefab, new Vector3(-301f,-3.1f,transform.parent.position.z + 500f),roadprefab.rotation);
}

}

2

The OnTriggerEnter will be called whenever the Object comes in contact with the trigger or colliders.
You need to have a check, that’ll see if the object is already created then you don’t need to instantiate it again.

Transform obj;
public Transform roadprefab;
 void OnTriggerEnter(Collider other)
 {
if(obj!=null){
     obj = Instantiate(roadprefab, new Vector3(-301f,-3.1f,transform.parent.position.z + 500f),roadprefab.rotation) as transform;
 }
}
3

Assets/roadpref.cs(12,13): error CS0029: Cannot implicitly convert type UnityEngine.Transform' to UnityEngine.GameObject’ ??