vertical automation lines

hey, i am working with very fast filter automation and want perfectly vertical automation lines so that it goes straight to the vaulue i need it to, not go on a very fast ramp, as it sounds right now, i have seen the automation that looks like an "L" with a point at the top of it but i dont know how to insert them, i'm sure its just a keyboard shortcut or a drop down thing but cant see it anywhere in the settings or manual, HELP!
thanks