[D20 Legends Project] Ashiel's Crunchy but Approachable D20

[Klara Meison]

How do Lines of Sight and Lines of Effect work? Pathfinder rules are delightfully unhelpful on the topic.

A line of effect is a straight, unblocked path that indicates what a spell can affect. A line of effect is canceled by a solid barrier. It's like line of sight for ranged weapons, except that it's not blocked by fog, darkness, and other factors that limit normal sight.

So far so good. LoE is blocked by solid barriers, and has to be straight. Rules then further clarify somewhat what consititutes a "solid barrier" and what doesn't:

An otherwise solid barrier with a hole of at least 1 square foot through it does not block a spell's line of effect. Such an opening means that the 5-foot length of wall containing the hole is no longer considered a barrier for purposes of a spell's line of effect.

Great, very clear, you need at least one 1ft hole per 5ft of the wall to make it transparent as far as LoE. But then you may think "hold on, what if it's a 0.5 ft hole? That's a pretty big hole, it shouldn't block LoS, right?". Well, not quite:

A line of sight is the same as a Line of Effect but with the additional restriction that that it is blocked by fog, darkness, and other factors that limit normal sight (such as Concealment).

So according to that passage you can't see those chairs, since they are behind solid barriers made of glass that don't contain any 1ft holes. Since those glass walls would obviously provide cover to any creature behind them, someone sitting in one of those chairs could use stealth to hide from you. Even though you can clearly see them. Likewise, you can't teleport into that room using, for example, Dimension Slide since you don't have Line of Effect to it's insides. -_-

Finally, consider this combination of one passage from the rules:

You must have a clear line of effect to any target that you cast a spell on or to any space in which you wish to create an effect. You must have a clear line of effect to the point of origin of any spell you cast.

And this architectural feature. Does that "window" block LoE or not? Can a dastardly villain cast Dominate Person on that lady while chilling in his armchair, or is she saved by the fact that that wall has no 1ft holes in it? I'd say you could shoot through that window, since holes are quite large enough to let an arrow pass through, so it shouldn't block LoS when it comes to either sight or ranged weapon attacks.