Common problems of unity (1)

1. Modify object position  

You cannot directly modify the of an object position

​
//transform.position.y = 10f;  The wrong way to write 

// correct 
Vector3 pos = transform.position;
transform.position = new Vector3(pos.x,20f,pos.z);

​

2. When objects collide with each other, both sides must Collider One of them also has Rigidbody

 3. target.position - transform.position What you get is not only direction, but also size

public class Notest : MonoBehaviour
{
    public float speed= 5f;
    public Transform target;

    void Update()
    {
        // Note that this is not a unit vector    target.position - transform.position 
        transform.position = transform.position + (target.position - transform.position) * speed * Time.deltaTime;
        //(target.position - transform.position).normalized  normalization 
        transform.position = transform.position + (target.position - transform.position).normalized * speed * Time.deltaTime;
        // improvement ： stay update The position is calculated once for each frame in the , The above occurrence vector and number are calculated twice . Add parentheses , Into a vector sum, only one operation is performed   It reduces the amount of computation 
        transform.position = transform.position + (target.position - transform.position).normalized * (speed * Time.deltaTime);
    }
}