Dear Peter, This indeed resolves the problem. Many thanks. My apologies for not starting a new thread. I am a new R user and not yet fully integrated into the R community. Kind regards, Bart Ferket -- View this message in context: http://r.789695.n4.nabble.com/rcspline-problem-tp3501627p4637181.html Sent from the R help mailing list archive at Nabble.com.