Why won't this method work?

I've recently been using Region3 and the method :FindPartInRegion3. But now this method seems not to work. This here is my code:

function Record()
    local room=Region3.new(script.Parent.Recorder.Position, Vector3.new(script.Parent.Recorder.CFrame.p*CFrame.new(script.Parent.Recorder.Size.X, script.Parent.Recorder.Size.Y, -RD.Value).p))
    local parts=workspace:FindPartsInRegion3(room, script.Parent.Recorder)
    local keyframe=Instance.new("Folder", D)
    keyframe.Name="Keyframe"
    for _, part in pairs(parts) do
        print("hi")
        local newdata=Instance.new("StringValue", keyframe)
    end
end

D is a variable for the distance the for the Region3. I'd really much appreciate any help. I've put parts all around the part called Recorder, but still no change.