Rescaling mesh or GameObject to fit in GUI Rect

Questions & Answers
1

Hi guys. I’ve got some rectangle drawed with mouse

Vector3 topLeft = Vector3.Min(startPosition, endPosition);
Vector3 bottomRight = Vector3.Max(startPosition, endPosition);

//Screen space?
Rect rect = Rect.MinMaxRect(topLeft.x, topLeft.y, bottomRight.x, bottomRight.y);

and I’m trying to convert it into some gameobject by instantiating a prefab (basically a quad with attached mesh to it):

Vector3 worldPoint = Camera.main.ScreenToWorldPoint(new Vector3(rect.center.x, rect.center.y, 5));
GameObject go = (GameObject) Instantiate(prefab, worldPoint, Quaternion.identity);

It centers perfectly, but how do I resize it to fit exactly to the size of drawed rectangle?

I can’t wrap my head around it. Any ideas?

2

Ok, I’ve figured it out. Here’s a solution if anybody else will stumble upon such problem.

Mesh mesh = go.GetComponent<MeshFilter>().mesh;

Bounds bounds = mesh.bounds;

//Getting xMin and yMin
Vector3 min = new Vector3(rect.xMin, rect.yMin, 0);
Vector3 max = new Vector3(rect.xMax, rect.yMax, 0);
			
//Converting them to worldspace coordinates
min = Camera.main.ScreenToWorldPoint(min);			
max = Camera.main.ScreenToWorldPoint(max);

//Calculating width/height in world space coorinate-size
float width = max.x - min.x;
float height = max.y - min.y;

//Calculating scale factors
float widthScaleFactor =  (width / bounds.size.x);
float heightScaleFactor = (height / bounds.size.y);

Vector3 localScale = go.transform.localScale;

//Scaling object
localScale.x *= widthScaleFactor;
localScale.y *= heightScaleFactor;

go.transform.localScale = localScale;

Probably not the prettiest one, but it works.

3

Assuming the quad mesh’s dimensions are 1x1 units, you could set the instantiated object’s transform’s scale to be the same as the Rect’s width and height.

go.transform.localScale = new Vector3(rect.width, rect.height, 1);
4

This works pretty well, but its off when the models origin is not a center.