The previous reports from DDXP have been big on the generalities but the players have been barred from talking about specific mechanics, until now:
Considering the D&D Next Playtest in Light of the WotC Seminars.
"Stat wise, my character sheet featured the big six ability scores, as well as HP and AC. Saving throws and other defenses were gone. As Monte explained in the Skills and Abilities seminar, saves are now rolled based on your ability scores."
Okay, here's the big one. Saving Throws and Defenses (apart from AC) look to be gone.
"Skills provided situational bonuses to checks that were also based on ability scores. As Bruce Cordell and Monte discussed in the same seminar, the D&D Next skill system is currently open-ended. Rolling to use any skill is always resolved as an ability check. The skill itself simply provides a bonus to that particular ability check in a specific situation."
The free-form skill system is pretty much like what I've got in
Heroes Against Darkness, where they depend on the sorts of things a character would be good at and the DM has the discretion to apply bonuses as appropriate.
The big takeaway here is that if the DC of the ability check is lower than your Ability Score, it's an automatic success.
"I felt the mechanic of the attacker (our wizard) setting the DC for the defender added tension to the fight, and differentiated her attacks nicely from standard melee or ranged attacks."
[UPDATED BELOW]
Another interesting aspect here. Basically, a magical attacker must add their appropriate number to a base, which then becomes the DC that the target needs to beat with their ability test (remember that defenses and saves are gone).
Speculating here, but my first guess is that it goes like this:
• DC = 10 + Caster's Ability Modifier (Int or Wis depending on the class)
Then the target must beat 14 (10 + 4) on an Ability Test.
However, this means that a caster targeting a caster of the same level will always fail (because the target's ability score is always going to be higher than the caster's DC).
So, maybe the DC calculation is higher:
• DC = 15 + Caster's Ability Modifier (Int or Wis depending on the class)
This resolves the problem with casters attacking casters, but it makes the saving throw/ability test much too hard for non-casters (DC 19 or so).
So, maybe saving throws/ability tests in combat are resolved differently to skill checks. Maybe you don't automatically succeed if your ability score is high enough. This would allow the first formula to work:
• DC = 10 + Caster's Ability Modifier (Int or Wis depending on the class)
Again the DC is 14, so a caster who has a +4 modifier in the appropriate ability score would have a 50% chance of saving against the spell. A normal monster or player character would probably only have a 25% chance of saving. Alternatively, if the game wanted to skew more towards avoiding the spells, the base for the DCs could be even:
• DC = 5 + Caster's Ability Modifier (Int or Wis depending on the class)
This could give a DC of 5-10 (depending on the ability score of the caster), giving similar casters a 75% chance of 'saving' and normal monsters and player characters about a 50% chance.
This is based on the assumption that the modifier range is -4 to +4 for starting characters. There's also talk of a much flatter progression curve, which means that +1 per level is GONE too.
[UPDATED HERE]
In various discussions it looks like the magic attacks may actually involve two rolls, one for the caster to determine the DC and then another 'saving throw' roll for the target. Ultimately, there are three viable options (four if no one rolls a dice):
• Caster rolls d20 + mods for DC, Target rolls d20 + mods to beat Caster's DC
• Caster calculates DC (e.g. 10 + mods), Target rolls d20 + mods to beat Caster's DC
• Caster rolls d20 + mods, compares to Target's ability score
Personally, this seems somewhat redundant to have both the caster and the target roll.
[UPDATED AGAIN: 30th May, 2012]
Now that we've seen the first open playtest rules, it turns out that I was right the first time. The DC for spells is automatically set by the Caster's magic ability score mod + 10:
• DC = 10 + Caster's Ability Modifier (Int or Wis depending on the class)
And the automatic pass mechanic has been adjusted so that your ability score has to beat the DC by 5 before it's an auto success.
Here's the mechanic:
• Caster calculates DC (e.g. 10 + mods), Target rolls d20 + mods to beat Caster's DC