How to identify the pipe line elevation in CII model. Since when we define the wind load case through used defined option we need to fill the elevation & wind velocity. So i feel if we haven't identify the elevation in model we can't get the correct load?

Please clear my doubts?

You're correct - as soon as you apply wind/wave loads you must correctly set the elevation of the first node in the model. You do this using the [Global Coordinates] option. (There is a toolbar button for this, a menu option for this, or you can use the key combination [Alt+G].

Remember that this elevation is the Distance above Grade which is usually NOT the plant/project elevation on your iso/dwg.

Input must be ELEVATION ABOVE GRADE.