Why isn't this Collision Detection working properly?

I have this placement system pretty laggy but works and i'm woundering why this collision detection isn't working or the part turning red if the some of the part is touching another park located in a folder in the workspace. The placed part goes into a folder named "Buildings" when placed but the collision isn't doing anything at all why?

local script: located in the startergui

game:GetService("RunService").RenderStepped:connect(function() -- Placement System
	if Selected then
		local X,Z = (Selected.Hitbox.Size.Z/2)%1,(Selected.Hitbox.Size.X/2)%1
		local p = CFrame.new(Vector3.new( (Mouse.Hit.x+(grid/2)) - (Mouse.Hit.x+(grid/2))%grid,Mouse.hit.y, (Mouse.Hit.z+(grid/2)) - (Mouse.Hit.z+(grid/2))%grid, Camera.CFrame.p))*CFrame.new(0,0,-0).p
		
		if Toration0 == 0 then X,Z = (Selected.Hitbox.Size.X/2)%1, (Selected.Hitbox.Size.Z/2)%1 end
		if Rotation0 == 0 then X,Z = (Selected.Hitbox.Size.X/2)%1, (Selected.Hitbox.Size.Z/2)%1 end
		
			local mouseposition = Vector3.new(X, Z)
			
			local magnitude, nearpoint = math.huge, nil
			
			for _,v in pairs(settings.gridindex) do
				for i,z in pairs(v) do
					
					local position = z.position;
						local pointmagn = (position.p - mouseposition).magnitude
						if (pointmagn < magnitude) then
							nearpoint, magnitude = Z, pointmagn
						end
					end
				end
			end
			
			if (Selected) then
				if (nearpoint.occupied) then
					Selected.Hitbox.SelectionBox.Color3 = Color3.new(1, 48/255, 51/255)
				end
			end
		
		Selected:SetPrimaryPartCFrame(CFrame.new(math.floor(p.X)+X,2.5,math.floor(p.Z)+Z)*CFrame.Angles(0,math.rad(Rotation), math.rad(Toration)))
	e