Transform

Every GameObject has a Transform. It stores where the object is (position), which way it faces (rotation) and how big it is (scale). It also stores the parent/child relationships you see in the Hierarchy.

World space vs. local space

This is the most important idea on this page.

• World values (position, rotation) are relative to the scene origin (0, 0, 0).
• Local values (localPosition, localRotation, localScale) are relative to the parent. The Inspector shows local values.

Example: a sword is a child of a hand. sword.localPosition stays at (0, 0, 0.5) while the character runs around, because relative to the hand it doesn't move. sword.position changes every frame. If an object has no parent, local and world are the same.

Properties

Methods

Code Samples

Moving and turning (no physics)

using UnityEngine;

public class TankControls : MonoBehaviour
{
    [SerializeField] private float moveSpeed = 5f;
    [SerializeField] private float turnSpeed = 120f; // degrees per second

    void Update()
    {
        float move = Input.GetAxis("Vertical");
        float turn = Input.GetAxis("Horizontal");

        // Moves along the tank's own forward, because Translate defaults to Space.Self.
        transform.Translate(Vector3.forward * move * moveSpeed * Time.deltaTime);
        transform.Rotate(0f, turn * turnSpeed * Time.deltaTime, 0f);
    }
}

Looping through children

// Hide all children of this object.
foreach (Transform child in transform)
{
    child.gameObject.SetActive(false);
}

Picking up an item into the player's hand

public void Equip(Transform item, Transform hand)
{
    item.SetParent(hand, false);      // keep local values, don't keep world position
    item.localPosition = Vector3.zero; // snap to the hand
    item.localRotation = Quaternion.identity;
}

Is the enemy in front of me?

Vector3 local = transform.InverseTransformPoint(enemy.position);
if (local.z > 0f) Debug.Log("Enemy is in front");
if (local.x < 0f) Debug.Log("Enemy is to the left");

What happens at runtime

Common Mistakes

• transform.position.x = 5; doesn't compile. position returns a copy (Vector3 is a struct). Copy it, change it, assign it back:

  Vector3 p = transform.position;
  p.x = 5f;
  transform.position = p;
  

• Doing math on eulerAngles. Unity may return 350 instead of -10, or flip values like (180, 0, 180). Keep your own angle variable and set rotation = Quaternion.Euler(...) from it.
• Moving a Rigidbody with the Transform. Use Rigidbody methods instead; see Rigidbody.
• Non-uniform scale on parents (like 1, 3, 1) makes rotated children look skewed. Scale the child mesh instead of the parent.

See also

• Vector3
• Quaternion

This page is a simplified, AI-assisted interpretation. For the complete and authoritative reference, see the official Unity documentation.