Can you intentionally lower a spell's DC if you cast it?

[Taku Ooka Nin]

Hey guys, so I was just rolling an idea around in my head involving shadow conjuration spells and saves.

Is it possible to intentionally lower a spell's Save DC?
Case in point: If I cast a Shadow conjuration spell to create a permanent artificial bridge, and then someone walks across it they get an automatic save against it. If they fail this save, they begin to sink through the now 20% real bridge until they fall through it.

So, if possible I'd like to make the DC as low as possible, if I am designing it as a clever trap.

[Cuuniyevo]

You can lower the CL when making potions and scrolls, but I do not know of a specific rule about normal casting.

In your example, why would you want to lower the save of that bridge trap? The lower it is, the less likely it is that anyone will actually fall through it. Do you want to make sure it's easy enough that your friends won't fall, but still high enough that your enemies will? That's a very dangerous balancing act, and your friends could still flub a roll, so I'd advise against it.

[wraithstrike]

No you cant lower the DC but if someone has proof that an illusion is not real they either get a bonus or they dont have to save. I forget which but the rule is in the magic chapter. Just tell your friends the bridge is not completely real.

Also which spell are you trying to emulate?

[Wyntr]

wraithstrike wrote:

No you cant lower the DC but if someone has proof that an illusion is not real they either get a bonus or they dont have to save. I forget which but the rule is in the magic chapter. Just tell your friends the bridge is not completely real.

Also which spell are you trying to emulate?

It varies based on proof versus being told (and might depend on GM interpretation).

Saving Throws and Illusions (Disbelief):

A character faced with proof that an illusion isn't real needs no saving throw. If any viewer successfully disbelieves an illusion and communicates this fact to others, each such viewer gains a saving throw with a +4 bonus.

[Taku Ooka Nin]

I would be using Greater Shadow Conjuration to make a Wall of Stone as a bridge. I'd leave fairly large holes in the middle for people to fall through.
There would be a permanent silent image over it, so someone would realize that there is an illusion.
Gasp!
Is the Stone Bridge also an illusion?!
*Disbelieves the illusion, starts sinking through the bridge.*
Great Scott! It is an illusion!
*Everyone else automatically makes the save against the bridge and begins sinking through it as well.*
Hehehehehehehehe. The GM's trap has worked with flying colors. *cackles*

I might even put something there that forces the PCs to interact with the silent image, or put a fake hook ring somewhere. Objects auto-succeed, so the grappling hook would auto succeed, thereby informing the PCs that it is an illusion.
*rubs hands together.*

[kestral287]

Believing that there are holes in the bridge covered by an illusion doesn't connect to "I must be standing on an illusion". They'd check to save against the Silent Image, but would have no reason to think that the bridge itself is false. That's honestly kind of a moot point because they would have to roll a save as soon as they stepped on the bridge-- that's interacting with it. Which, if they're sinking slowly, should give them time to just... take a step back.

You really need the forced interaction for it to work but the Silent Image shouldn't do anything.

And you don't really want a terribly low DC, because it needs to be high enough that they don't disbelieve until they're part of the way across it and you use whatever interaction to reveal it as an illusion that you have in mind.

In fact, on that note-- if possible you should use multiple Shadow Conjurations. They'd have to make a save against each section, and that gives you more bridge space to play with as well to make retreat harder. It might even get them to keep going forward-- they disbelieve one section, see it as a Shadow Conjuration, rush to the next section... make another Will save. And now they can't go back.

[Deighton Thrane]

There's a few things I see wrong with this. The Shadow style of illusions create quasi-real effects, be they creatures or objects. Objects created with Greater Shadow Conjuration either cause 60% damage when resisted, or have 60% strength. It doesn't say anything about being less real than before. If the bridge was real enough to walk on before you make the save, it should be real enough to walk on after. Only now it has 60% of the HP it normally would have.

Even if you don't read the shadow illusions have real effects the same way I do, characters can still choose to fail the will save to disbelieve the illusion. So suddenly it becomes a "if you believe in it, it's real" situation where characters can choose to believe it's real.

[Moppy]

core rulebook wrote:

You can cast a spell at a lower caster level than normal, but the caster level you choose must be high enough for you to cast the spell in question, and all level-dependent features must be based on the same caster level.

Rules for caster level say you can't lower the caster level to below that required to cast the spell. Save seems to be keyed off the caster level so it looks like you can't do this. However, if you had the spell at an increased CL (say you used a higher level spell slot for it) you could lower to the regular.

[Bandw2]

invent a new spell

[Rynjin]

Have your caster take a bunch of [Casting Attribute] Damage before casting it.

[Taku Ooka Nin]

I wouldn't do it and put it over a death pit of death.
It would instead lead to a potentially frightening scenario that is quickly resolved with a quick drop through a deeper darkness spell that has a silence spell put in it (both permanent, somehow) into a slide beneath so they don't actually take damage from the fall.

Then...by the gods! We're in one of Taku Ooka Nin's dungeons with no clear and easy way out! We can't turn and leave! We actually have to face the perils beyond like upstanding adventurers!

[Gauss]

Taku Ooka Nin, you are overthinking it. Just run it as a trap.

A bridge with a hole in it is basically just a pit.
A pit covered by an illusion is clearly a trap.
Follow the trap rules.

Come up with a Perception DC to detect the trap and a Reflex DC to avoid it.

Since this is spell based you can use the magic trap rules to arrive at the DCs.

[wraithstrike]

Wyntr wrote:

wraithstrike wrote:

No you cant lower the DC but if someone has proof that an illusion is not real they either get a bonus or they dont have to save. I forget which but the rule is in the magic chapter. Just tell your friends the bridge is not completely real.

Also which spell are you trying to emulate?

It varies based on proof versus being told (and might depend on GM interpretation).

Saving Throws and Illusions (Disbelief):

A character faced with proof that an illusion isn't real needs no saving throw. If any viewer successfully disbelieves an illusion and communicates this fact to others, each such viewer gains a saving throw with a +4 bonus.

I agree but if your caster buddy tells you I think most GMs would let it go.