Check object within a radius building

Hi guys. To check that player within the building. I use:

Code:

buildingPrivlidges = typeof(BasePlayer).GetField("buildingPrivlidges", (BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance | BindingFlags.NonPublic));
List<BuildingPrivlidge> playerpriv = buildingPrivlidges.GetValue(player) as List<BuildingPrivlidge>;
if (playerpriv.Count == 0)

How to check the other objects?

 

you can look at my zone manager, i use a lot this.

 

Code:

bool findCupboard = false;
foreach(Collider col in Physics.OverlapSphere(entity.transform.position, 30))
{
    if(col.name == "items/cupboard.tool.deployed")
    {
        findCupboard = true;
        break;
    }
}

This code can be optimized? I do not understand how to work with masks and what they do.

Sorry for my bad English ...