RendererのBoundsを設定する

BoundsSetter.cs

namespace hoge.hoge
{
    using UnityEngine;

    public class BoundsSetter : MonoBehaviour
    {
        [SerializeField]
        private Vector3 targetBoundsSize;

        private void Start()
        {
            this.SetBounds();
        }

        [ContextMenu("SetBounds")]
        private void SetBounds()
        {
            Bounds currentBounds = this.GetComponent<Renderer>().localBounds;
            currentBounds.extents = this.targetBoundsSize;

            this.GetComponent<Renderer>().localBounds = currentBounds;
        }
    }
}