|
Vigorous Motion
If you are riding on a moving mount, taking a bouncy ride in a wagon, on a small boat in rough water, below-decks in a storm-tossed ship, or simply being jostled in a similar fashion, you must make a concentration check (DC 10 + the level of the spell you’re casting) or lose the spell.
Violent Motion
If you are on a galloping horse, taking a very rough ride in a wagon, on a small boat in rapids or in a storm, on deck in a storm-tossed ship, or being pitched roughly about in a similar fashion, you must make a concentration check (DC 15 + the level of the spell you’re casting) or lose the spell. If the motion is extremely violent, such as that caused by an earthquake, the DC is equal to 20 + the level of the spell you’re casting.
You can cast a spell normally if your mount moves up to a normal move (its speed) either before or after you cast. If you have your mount move both before and after you cast a spell, then you’re casting the spell while the mount is moving, and you have to make a concentration check due to the vigorous motion (DC 10 + spell level) or lose the spell. If the mount is running (quadruple speed), you can cast a spell when your mount has moved up to twice its speed, but your concentration check is more difficult due to the violent motion (DC 15 + spell level).
So, the following scenarios are covered if you cast:
-Mount stationary = No concentration check
-Mount single move = No concentration check
-Mount double move = Concentration check (vigorous motion DC)
-Mount running = Concentration check (violent motion DC)
How do GMs handle concentration checks for when your mount attacks and you cast a spell before or after? Obviously there will probably be table variation, but do these seem reasonable options to offer up to a GM?
-Mount stationary, makes single standard action attack, you cast before or after that attack = No concentration check
-Mount move + standard attack = Concentration check (vigorous motion DC)
-Mount charge attack = Concentration check (vigorous or violent motion DC)
-Mount full attack = Concentration check (violent motion DC)
Seems reasonable to me.
Cast a Spell: You can cast a spell with a casting time of one standard action or less normally if your mount makes a single move. You can cast the spell either before or after your mount moves, and the rules assume your mount is stationary when you cast.
If your mount makes a double move, then you're casting the spell while the mount is moving, and you have to make a Concentration check due to the vigorous motion (DC 10 + spell level) or lose the spell. If the mount is running, your Concentration check is more difficult due to the violent motion (DC 15 + spell level). In either case, you cast your spell when your mount has completed half its movement for the turn.
Your mount's movement has no effect on how you aim most spells. If the spell requires you to make a ranged attack roll, you take penalties if your mount makes more than a single move, as noted in the section on ranged attacks. If the spell requires you to make a melee attack roll, you're subject to the limitations listed in the section on melee attacks.
Quoted from the old 3.5 rules faq.