就是找出 bounds max的一个点，计算与摄像机的距离,然后确定它 https://answers.unity.com/questions/13267/how-can-i-mimic-the-frame-selected-f-camera-move-z.html
Bounds CalculateBounds(GameObject go) { Bounds b = new Bounds(go.transform.position, Vector3.zero); UnityEngine.Object[] rList = go.GetComponentsInChildren(typeof(Renderer)); foreach (Renderer r in rList) { b.Encapsulate(r.bounds); } return b; } public Vector3 FocusCameraOnGameObject(Camera c, GameObject go) { Bounds b = CalculateBounds(go); Vector3 max = b.size; // Get the radius of a sphere circumscribing the bounds float radius = max.magnitude / 2f; // Get the horizontal FOV, since it may be the limiting of the two FOVs to properly encapsulate the objects float horizontalFOV = 2f * Mathf.Atan(Mathf.Tan(c.fieldOfView * Mathf.Deg2Rad / 2f) * c.aspect) * Mathf.Rad2Deg; // Use the smaller FOV as it limits what would get cut off by the frustum float fov = Mathf.Min(c.fieldOfView, horizontalFOV); float dist = radius / (Mathf.Sin(fov * Mathf.Deg2Rad / 2f)); Debug.Log("Radius = " + radius + " dist = " + dist); c.transform.localPosition = new Vector3(c.transform.localPosition.x, c.transform.localPosition.y, -dist); if (c.orthographic) c.orthographicSize = radius; // Frame the object hierarchy c.transform.LookAt(b.center); var pos = new Vector3(c.transform.localPosition.x, c.transform.localPosition.y, dist); return pos; }