Fusion Expression

[duccio lucchesi]

hello!
i come from nuke and i use a lot the TCL expression “frame%1*X”, the operation basically create a ramp every frame from 0 to 1 multiplied by X value.
i use it to create motion blur effect without move my subject, more or less like directional blur.
there is a way to do the same in Fusion?
i try with “frac(time)” expression, it does allmost the same result, but only in frame 0.

thanks!
Duccio