Just did some quick testing - the doors definitely have physics and can get stuck on objects and can impart forces. But unimpeded yes, they smoothly open/close.
I stuck a tire in a door frame and tried to close it, the tire emitted a bunch of dust clouds as the two objects fought before the door finally ejected the tire at high speed.
In Half-Life 1 there is a map with two doors that deal negative crushing damage, so you can wedge yourself in them to give yourself a massive over heal
I stuck a tire in a door frame and tried to close it, the tire emitted a bunch of dust clouds as the two objects fought before the door finally ejected the tire at high speed.