Dear Richard,

When i try modelling elbow 45 degree, a warning show up that tell the bend is over 5 degree, what is this meaning?
so i modelling it by give the radius by 0.625 NPS. am i doing right with that in CAESAR?

You probably don't want to change the radius. If you have a "long radius" elbow, regardless of the angle, the radius is 1.5*Nominal_OD.

To model a 45 deg bend, assuming you start from the "X direction" and turn up in the "Y", the next element would be defined as "DX=delta" and "DY=delta".

i see, so it will be an offset, and just don't change anything in bend input.
Thanks Richard.......

No, not really an offset. Think of how you would build the model, using just "delta dimensions", the bend just defines SIFs. So you would have something like this:

10-20
DX=10
(bend at 20)

20-30
DX=7, DY=7

30-40
DX="next value", DY="next value"