NGUI position to World position

Vector3 v = Camera.main.WorldToScreenPoint( building.center.position );

        v.x = ( v.x / Screen.width ) * 720.0f;

        v.y = ( v.y / Screen.height ) * 1280.0f;

        uiSelectItem.transform.localPosition = v - new Vector3( 720.0f / 2.0f, 1280.0f / 2.0f, 0.0f );

 

var worldToViewportPoint = this.cameraForTarget.WorldToViewportPoint(pos);
var viewportToWorldPoint

= this.cameraForUi.ViewportToWorldPoint(worldToViewportPoint);