How to determine visibility for cover / partial cover

[RedDogMT]

So, I understand how to determine if a target has cover for both melee and missile attacks (using the corners of the squares). However, it seams to me that visibility is not determined in the same way. I have been unable to find any guidelines in the rulebook for how visibility is determined.
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For example, from the PRD:
Partial Cover: If a creature has cover, but more than half the creature is visible, its cover bonus is reduced to a +2 to AC and a +1 bonus on Reflex saving throws. This partial cover is subject to the GM's discretion.

As best as I can tell from reading the rules and the Ogre example from the section on cover, visibility would likely be determined by drawing a cone from the center of the attacker to the 'visible' portions of the target. If 50% or more of the target is not visible, the target has normal cover. If more than 50% is visible, the target has partial cover.

Is this the correct way to determine visibility? If not, what is?

I've done some searching in the forums, but did not come across any definitive answers. Thanks guys.

[Nefreet]

Can you see their square? If the answer is "yes", then you have visibility.

[RedDogMT]

Hi Nefreet, thanks for the reply, but the question was related to how to determine the degree of visibility for deciding if a target has cover or partial cover.

Every target that has cover is visible to some extent (except for total cover).

[Nefreet]

There are no "degrees of visibility". You either see your target, or you don't.

Unless I'm just not understanding your question. You already quoted the rules for how one determines partial cover.

[Honorable Goblin]

I believe RedDogMT is asking how a GM is supposed to go about determining whether or not "more than half the creature is visible" so as to treat it as having partial cover instead of "normal" cover.

[Nefreet]

As is quoted, it is up to a "GM's discretion".

Is half the square visible? Are two corners visible? Is a Halfling the only thing standing in the way of your medium-sized target? This is up to you to decide.

[RedDogMT]

Honorable Goblin wrote:

I believe RedDogMT is asking how a GM is supposed to go about determining whether or not "more than half the creature is visible" so as to treat it as having partial cover instead of "normal" cover.

That is correct. I am asking if there are guidelines in the game for determining this.

I don't expect Paizo to spell everything out, but since they gave us guidelines for determining cover based on using the corners of squares, I hope it makes sense to ask if there are rules to determine how visible a creature is. If it's up to GM discretion, then I can obviously do anything I want...which is what I would do anyway if there was no guideline... :)

[Nefreet]

Use the suggestions I outlined right above your post?

[Greylurker]

I generally work like this;

Pick a corner of the guy doing the shooting's square.

From that corner draw an imaginary line to each corner of the Target's Square.

If something gets in the way of all four lines he has full cover.
If 1 or 2 of the lines are clear then it's partial cover

[RedDogMT]

Nefreet wrote:

Use the suggestions I outlined right above your post?

...or use the method that I posted in the first post?

[RedDogMT]

Greylurker wrote:

I generally work like this;

Pick a corner of the guy doing the shooting's square.

From that corner draw an imaginary line to each corner of the Target's Square.

If something gets in the way of all four lines he has full cover.
If 1 or 2 of the lines are clear then it's partial cover

Thanks Grey,

Your suggestion is appreciated. Your reply isn't snarky like another certain someone on this thread.

[Nefreet]

Whatever you decide to do, be sure to tell your players up front.

I can tell you now that having two different rules for determining cover (using corners) and visibility (center of square) will only confuse and aggravate your players.