Here's an example for you, look at this pic of a cheap aftermarket HID kit, fitted in to a headlamp designed for a halogen bulb. See how the light pattern is everywhere and there is no distinct cut off. (pic shamelessly nicked from another thread on here)



Then this is my car, the halogen housings have been changed for some designed to be used with a HID bulb, I also have a cheap HID kit. Sorry the pic isn't very good, only one I've got!