Happened to me a few weeks ago in a game against one of the guys at my LGS. I let him take the shot but I definitely was not pleased with the physics behind this situation.
Not sure if this pic will work but here:
If image does not show, here is the photobucket link:
[url]http://i672.photobucket.com/albums/vv86/w7west/situation.png[/url]
So basically what is going on here is that his autocannon dred (polygon + double lines for autocannon) is shooting at my raider (triangle), over a rhino (rectangle).
The red line represents the arc of sight that is blocked from my raider to the dred. Only things above this line would be able to see the raider. As you can see, the ends of his autocannons are protruding above this line due to rare earth magnets letting him pivot the arms vertically.
My problem with this was that although the barrels were indeed not blocked by the rhino, they were clearly pointing in a trajectory that would sail far above my raider.
Does the weapon need to be aligned with it's target in the vertical plane in order to shoot?
If so, the autocannons would need to fall below the red line in the diagram, meaning they would not have line of sight.
If not, would you be ok with someone who models his autocannons sticking at an extreme angle, perhaps even 90 degrees taking shots dead ahead?
Thanks guys, hope the image works.