How can I use the ease() function within an expression. I got something like this; if($F>20 && $F < 40, ease(30), 14)
but it didnt work…any input?

The ease() expression function doesn't take any arguments. Are you thinking of easep()? In either case, the interpolation will be based upon the key values at the ends of your channel segment.

shortly after I posted the problem I tried the easep() but it didnt work. It doesnt show me that is a syntax problem, so i dont know what i'm missing as yet

To get help on a function, open the textport then type exhelp easep()

Your expression is still wrong actually even if you do use easep() then. I'm assuming that you want to ease into a value of 30 from 14 in between frames 20 and 40?

I think the easiest way is to do it directly. Set the appropriate keys on your parameter and change them to constant() or ease() at the right spots. Remember that expressions in Houdini are simply special cases of channels.

the funny thing is that I tried using it but the values go negative.