A wall of force is an invisible Wall.
If a creature was to attack said wall after determining it was there would the creature have to roll a miss chance?
My thought was yes because it is invisible and has ac/tac. A invisible creature that is sensed has a dc11 miss chance. So it equates to you swing at the wall and just misjudge how far or close the wall was to you.
Nah, the miss chance is because a creature can theoretically move around and doesn't occupy a whole cube.
The wall is a very large and doesn't move. Once you've identified its presence, it's pretty difficult not to hit it.
So no, I wouldn't allow for a miss chance to be applied to something like this.
They should spend no more than an action to verify the position and can repeatedly hit it. That's why I feel a miss chance is in appropriate. Basically if you take the invisible part to heart, then you would need some sort of action to become aware of it in the first place, which would also reveal it's location, and since it doesn't move it's not appropriate IMO to have a miss chance due to invisibility.
As well, we could go with other responses:
1) The call out as an "invisible wall" is descriptive text and not really meant to have mechanical implications
2) Invisible conditions only actually addresses invisible creatures, not objects. The DC 11 flat check only applies to creatures as such.
I mean you would need to figure out it's there in the first place since it is invisible. Which I said the creature was aware of the wall.
It's the fact that they have given the walls AC/TAC which means you have a chance of not hitting the wall normally. Add to that the fact that you can't see the wall and you have a flat check miss chance.
You don't really have a chance of not hitting the wall though.
It's a 6th level spell (requires level 11). Assuming you are within 3 levels of the spell caster, level 9 and that you are at least trained with the weapon you attack with you have at least a +9 to attack. Anyone attacking with a weapon will probably be better than trained and probably have an attribute bonus to their attack. Which is going to put the roll at "don't roll a 1".
Honestly, this is AC in the sense that targeting a square in PF1 had an AC of 5.
Again, the rules should probably directly address the issue as right now you're extrapolating.
I assert that the "invisible wall" bit is more descriptive and not a function of actual invisibility per the spell. And it's also noteworthy that the invisible condition only explains what happens for creatures, not for objects.
If you want to note:
Hey, this is an area which probably needs to be specifically addressed instead of requiring people to infer!
Then I absolutely agree with you.
Here is my guess about how Paizo actually intended it work after stepping back and thinking about it.
They gave it both AC and touch AC to represent that trick nature of hitting an invisible, but inanimate object. Meaning you don't make the flat check like you would against an invisible creature, but still have to make an attack roll.
Are any buildings or other large objects given AC or touch AC?
The other wall spells all hold the same AC/TAC. So it can't be an AC designed based on the invisibility.
Even if the wall isn't a creature it's still invisible. Saying its invisible as a descriptor, which is the only way that word would be used anyways, means something.
A petrified/paralyzed invisible creature would still have the benefit of the miss chance so why wouldn't the wall. Does the fact that something has sentience make it harder to hit while invisible?
The fact that a petrified or paralyzed invisible creature would have miss chance is more a quirk of the rules than a feature.
Again, I assert your point out sore spots of the rules where they don't work well and lead to basically nonsense.
If you've located a petrified invisible creature, you shouldn't really have a chance to miss it. You have to spend some sort of action to initially find it, but then you should be good.
The reason for invisibility to give a miss chance is because creatures are typically moving.
And no, saying something is invisible doesn't necessarily mean anything. PF1 is full of flavor text that had no actual mechanical effect and there was no end of people who insisted that it did. Eventually the designers had to say that flavor text didn't mean anything mechanically.
I'm sure if I go searching through monster and spell descriptions I can find a plethora of flavorful descriptions that don't have mechanical effects.
IMO, the chance to hit something/someone is actually the chance to land a square hit that will do damage and not the chance to just make contact. In that context, a "miss" chance on an invisible wall makes sense, you misjudge the angle or the distance (or whatever) and just hit a glancing blow that doesn't do any damage.
And yeah, TAC seems to make this incorrect, but it works for my headcanon.