sorry for the late reply but you wanna do something like this:
local region = Region3.new((RootPart.CFrame + Vector3.new(-5,-5, 5)).Position, (RootPart.CFrame + Vector3.new(5, 5, 15)).Position)
Note you can’t adjust the rotation of a region3 tho EgoMoose did make a module for that purpose. Rotated Region 3 Module