Casting on the Defensive

[rgrove0172]

What exactly is "Casting on the Defensive"? Cant seem to locate a simple explanation.

Oh and while Im at it, do the magic classes use the "Use Magic Device" skill? Im thinking not.

[Lifat]

When a spellcaster casts a spell he provokes attacks of opportunities from all melee attackers. Normally the spellcaster would be out of reach but if he isn't he can "cast on the defensive" which requires him to make a concentration check to succeed. (DC = 15+(2x spell lvl)). His concentration modifier is his caster lvl + casting stat modifier. (plus whatever other bonus he has scrounged up such as trait bonus or feat bonus).
If he is succesful the spell goes of and no attack of opportunity is made.
If he fails the spell fizzles and no attack of opportunity is made.

[Xaratherus]

For your reference, you can find the relevant section here on the PRD. I won't bother restating as Lifat has the correct answer there.

As to Use Magic Device: That is used to activate scrolls, wands, rods, etc. Magic-users can still need UMD; if the wand, scroll, etc. is a spell that is on their spell list, they don't need to make a UMD check, but if it is a spell not on their list, they can still use the item but have to make a UMD check to do so. You can read about the skill here; note the section regarding emulating and using scrolls or wands, as those can apply to even magic users.

[Lifat]

Also note that "on his spell list" isn't his spell known (in the case of wizard/sorcerer for an example) but whether or not it is a spell they COULD know.
Take the wizard Raistlin who picks up the wand of fireball. Raistlin is only lvl 4 so he doesn't know fireball but it is on the wizard spell list so Raistlin doesn't need Use Magic Device to activate the wand (he does however need the command word).
Take the same wizard who picks up wand of cure light wounds. That spell is not a wizard spell so Raistlin would need Use Magic Device.

[Renen]

[http://lmgtfy.com/?q=pfsrd+casting+defensively]Let me google that for you[/url].

[rgrove0172]

Ok thanks, I do find it odd that Use Magic Device is not a class skill then for Wizards.

So in the typical situation where a wand is found in a treasure trove, somebody would have to use Spellcraft to try and identify what the wand did and perhaps how to trigger it. If it was something a mage was familiar with (One of his class spells) he could trigger it automatically but otherwise would have to use UMD each time he pulled it out.

Right? Im assuming Spellcraft works that way? How else would you learn the command word of some random ancient artifact?

[Kalshane]

Yes, if he makes the necessary Spellcraft check to identify the item, he knows how to activate it.

[Lifat]

rgrove0172 wrote:

Ok thanks, I do find it odd that Use Magic Device is not a class skill then for Wizards.

So in the typical situation where a wand is found in a treasure trove, somebody would have to use Spellcraft to try and identify what the wand did and perhaps how to trigger it. If it was something a mage was familiar with (One of his class spells) he could trigger it automatically but otherwise would have to use UMD each time he pulled it out.

Right? Im assuming Spellcraft works that way? How else would you learn the command word of some random ancient artifact?

You are right on track. I think UMD was mostly meant for non-spellcasters such as rogues but the difference between having it as a class skill or not having it isn't that big in pathfinder.

A class skill simply means that when you put the first rank into the skill you get a bonus of +3. At lvl 20 assuming both have 0 feats, ability score mod and other bonuses a wizard would have +20 while the rogue would have +23 (again assuming both use max ranks)

[blahpers]

That +3 makes a big difference before you get to level 20, though.

[DesolateHarmony]

(I play wizards.)

Usually wizards are hubristic, and spells not on their list aren't important enough to bother with. They can already use most magic devices, and can figure things out quickly enough to use other methods. =)

Sorcerers are generally more empathetic, and get things to cooperate with them. So, they both have better charisma, and UMD as a class skill.

Note, there is a feat or trait (don't remember it offhand), to let you use UMD with Intelligence, and there are traits to give UMD as a class skill. So, it can be done by a wizard.

[blahpers]

Hah! I like that interpretation! If a wizard wanted to use that spell, they'd go research a better, more WIZARDLY version of that spell, or they'd craft a wondrous item that did it for them (+5 DC? Pshaw!).