Generic "Knockback" Spell Questions

I'm only theorizing, but are knockback spells simply moving a unit a large number of times in small increments of distance to create the illusion of being knocked back, or are there some tricks in doing that I am not aware of? In particular, I'm worried over collision detection and terrain stuff (such as what happens if a unit got pushed into boundaries where units aren't supposed to be in)?

And how would it be best to actually move the hit unit?
-Through setting the direction of the attacking unit's to a variable and then moving the defending unit in the direction of the variable?
-Using triangles to find out where to move the unit?
-Using circles?

I have a rough sketch of it in my mind, but I'm not certain how I should implement it.

Polar Offset. (ie the first one)

If you don't want the target to be stunned by the effect, use call SetUnitX(unit,real) and call SetUnitY(unit,real), as this doesn't interrupt orders.