--Location of RegionCulling can be anywhere the client can see.
--Using the main module is not required, but it does reduce setup a bit for most cases.
local RegionCulling = require(game:GetService("ReplicatedStorage"):WaitForChild("RegionCulling"))
local RegionState = RegionCulling.RegionState
local ModelCulling = RegionCulling.ModelCulling

--Optional - Change the time hidden region events are delayed.
RegionState.HiddenRegionTimeout = 2

--Add 3 regions.
--Region 1 is made of 2 zones.
--Region 3 can be seen when the camera is outside the regions.
RegionState:AddRegion("Region1", CFrame.new(0, 0, 0), Vector3.new(2, 2, 2))
RegionState:AddRegion("Region1", CFrame.new(0, 4, 0), Vector3.new(2, 2, 2))
RegionState:AddRegion("Region2", CFrame.new(0, 0, 4), Vector3.new(2, 2, 2))
RegionState:AddRegionFunction("Region3", function(Position: CFrame): boolean --Function-based regions can be used for custom cases.
    return Position.Position.Magnitude < 10
end)
RegionState:SetVisibleWhenOutsideRegions("Region3")

--Make it so region 1 can see 2 and 3.
--ConnectRegions makes it so both regions can see each other.
RegionStateObject:ConnectRegions("Region1", "Region2")
RegionStateObject:ConnectRegions("Region1", "Region3")

--Set up the models (next section)

--Start the update loops.
--Camera:GetRenderCFrame() is used for checking where the player is.
RegionCulling:Start()

--Location of RegionCulling can be anywhere the client can see.
--Using the main module is not required, but it does reduce setup a bit for most cases.
local RegionCulling = require(game:GetService("ReplicatedStorage"):WaitForChild("RegionCulling"))
local RegionState = RegionCulling.RegionState

--Listen to events being shown or hidden.
RegionState.RegionVisible:Connect(function(RegionName: string) ... end)
RegionState.RegionHidden:Connect(function(RegionName: string) ... end)

--Check if a region is visible.
local VisibleRegions = RegionState:GetCurrentVisibleRegions() --List of the region names that are visible
local IsVisible = RegionState:IsRegionVisible("Region1") --Bool for if a region is visible
local InRegion = RegionState:IsInRegion("Region1", Vector3.new()) --Bool for if a point is in a region

--Location of RegionCulling can be anywhere the client can see.
--Using the main module is not required, but it does reduce setup a bit for most cases.
local RegionCulling = require(game:GetService("ReplicatedStorage"):WaitForChild("RegionCulling"))
local RegionState = RegionCulling.RegionState
local ModelCulling = RegionCulling.ModelCulling

--Optional - change the reparent operations per step and cluster size.
ModelCulling.ReparentOperationsPerStep = 300
ModelCulling.PartClusterSize = 75

--Set up the regions (previous section)

--Bind models.
--Multiple models can be found to a region.
--Can be safely done before and after starting the update loops.
local Context1 = ModelCulling:BindModelToRegion("Region1", game:GetService("Workspace"):WaitForChild("Model1"))
Context1:EnableFlattening() --Enables model flattening with the default reparent operations per step.
Context1:EnableClustering() --Enables clustering while flattening with the default cluster size.

local Context2 = ModelCulling:BindModelToRegion("Region2", game:GetService("Workspace"):WaitForChild("Model2"))
Context2:EnableFlattening(500) --Enables model flattening with a custom reparent operations per step.
Context2:EnableClustering(100) --Enables clustering while flattening a custom default cluster size.

local Context3 = ModelCulling:BindModelToRegion("Region2", game:GetService("Workspace"):WaitForChild("Model2A"))
--Context2:EnableFlattening() --Flattening is NOT enabled. EnableClustering() has no effect without EnableFlattening().

--Add filters for what parts to flatten.
--Filters return true if an instance can be flattened, with an optioanl string saying why they can't.
--Be aware a single instance not being flattened will result in the entire instance tree under the model being unflattened (see next section).
--Context3 is not passed in because EnableFlattening() was not called.
for _, Context in {Context1, Context2} do
    --A filter for Humanoids is not added because Humanoids are special-cased to move together.
    Context:AddFlatteningFilter(function(Child: Instance): (boolean, string?)
        return not Child:IsA("BasePart") or Child.Anchored, "Part is not anchored."
    end)
    Context:AddFlatteningFilter(function(Child: Instance): (boolean, string?)
        return not Child:IsA("BaseScript"), "Scripted instances are not safe to be flattened."
    end)
end

--Start the update loops.
--Camera:GetRenderCFrame() is used for checking where the player is.
RegionCulling:Start()