Gizmos.DrawSphere

public static void DrawSphere (Vector3 center, float radius);

説明

center と radius から球体を描画します

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void OnDrawGizmosSelected() {
        Gizmos.color = Color.yellow;
        Gizmos.DrawSphere(transform.position, 1);
    }
}