This cropped up in my recent games, as we have just added new terrain to our collections i,e hills, and the issue is the following, Do hills block LOS?
In both the Hordes and warmachine rulebook, under the LOS entry, it states to detemine if you have LOS to another model, you need to be able to draw a line to any part of its volume, from any part of the volume of your model.
LOS must not pass through any terrain piece.
Both my opponent and myself, assumed that a hill will block LOS, but upon recently reading the LOS rules, after this was pointed out to me, Both myself and my regular opponent are not 100% sure any more, because of the following.
My model is on 1 side of a hill, my opponants model is on the other side of the hill, The hill is 1" high, both models are on a small base, and thus have a volume of 1.75" high, this allows me to draw a line to my oppents model over, not through the hill, as both models are .75" higher then the hill.
So will this give me LOS to my opponents model, or will a hill reguardless of its hight block LOS to a model on the other side of it.
That's the sort of situation the volumes are for.
So yes you would be able to draw LOS.
But that is the default situation.
I don't have a rule book to hand, but I recall there being a bit in the terrain section where the players can also agree what a particular bit of terrain does before the game starts. So you can also have it blocking LOS if you both agree it does.