Scale Object Between Creation Point and Mouse Point

Question

I created a script that when I click on the terrain, It creates a cube prefab at that position.

When I move my mouse around the screen, the prefab does a LookAt() so the cube constantly looks at the terrain where the mouse is. What I can't get to work quite right is when I drag the mouse the cube should scale along the Z Axis Which it does but it scales at the middle of where it was created.

So I added this:

currentObj.transform.position = new Vector3(trs.position.x, trs.position.y, startPosition.z - distance);

Which moves it it a weird way that I can't explain, but it isn't correct. What I would like is for the cube to have one face where it was created and the other face at the location of the mouse (scaled along the Z Axis).

The if(started) block is where the issue lies in the code:

public class BridgeCtrl : MonoBehaviour {

    public GameObject bridge;

    GameObject currentObj;

    Vector3 mouseWorldPosition;
    Vector3 startPosition;

    bool mouseDown = false;
    bool started = false;
    bool bridgeBuilt = true;

    // Update is called once per frame
    void Update () {
        // Preview Bridge
        if(started){
            RaycastHit hit = GetWorldPosition();
            if(!hit.Equals(null)){
                currentObj.transform.LookAt(hit.point);
                Transform trs = currentObj.transform;
                float distance = Vector3.Distance(trs.position, hit.point);
                currentObj.transform.localScale = new Vector3(trs.localScale.x, trs.localScale.y, distance);
                currentObj.transform.position = new Vector3(trs.position.x, trs.position.y, startPosition.z - distance);
            }
        }

        // Start Bridge
        if(Input.GetMouseButtonDown(0) && !started){
            started = true;
            RaycastHit hit = GetWorldPosition();
            if(!hit.Equals(null)){
                startPosition = hit.point;
                currentObj = GameObject.Instantiate(bridge, startPosition, Quaternion.identity) as GameObject;
            }
        }
        // End Bridge
        else if(Input.GetMouseButtonDown(0) && started){
            started = false;
        }

        if(Input.GetKeyDown(KeyCode.Escape) && started){
            if(!currentObj.Equals(null)){
                GameObject.Destroy(currentObj);
                started = false;
            }
        }
    }

    RaycastHit GetWorldPosition(){
        RaycastHit hit;
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        Physics.Raycast(ray, out hit);
        return hit;
    }
}

So, how can I get this so it scales along the Z Axis between the creation point of the object and the mouse pointer?

you were so close :) you just need to take the cube width into account :) imagine this: your cube has scale of 1 and width of 3, so left side is at position 0, center is at position 1.5 and right side is set position 3. you now change the scale to 10. what you want is: left side at position 0, center at position 15 and right side at position 30. but your code gives you center at position of 1.5 - 10. i hope the explanation is clear enough - if it is not, i can write the formula for you :) — Jinjinov
I decided to do something different, which works better. I am repeating an item, then combining it into one item. The results look really nice! — Get Off My Lawn

maksymiuk maksymiuk · Accepted Answer · 2015-06-09T00:20:48

Have you tried utilizing a Ray?

Ray ray = new Ray(startPosition, (startPosition - hit.point));
currentObj.transform.position = ray.GetPoint(distance/2);

Scale Object Between Creation Point and Mouse Point

1 Answers