Interesting. I've thought about trying it but never committed to it. I am always looking for ways to speed up combat and make it more engaging. I am sure I can combine it with my cinematic initiative variant and see how the two work together.
@embee, how are you doing your calculations? Are you using the chart from the other page or something else?
For the DC, it's literally just adding 22 to the monster's To Hit bonus. The player rolls d20 and adds the result to their AC.
The Orc vs AC17 Player is a really good breakdown.
The Orc has a +5 to hit. Plus 22 is DC27. Player has an AC17. If they roll a 10 or higher, they dodge the attack.
That's a 55% chance to dodge. If I were to roll for the Orc, I'd have to roll a 12 or higher (12 + the +5 To Hit). That's a 45% chance to hit. It's a perfect mirror image.
It makes for very smooth play. Consider a player who wants to split their movement.
Player: I move to attack the Orc.
DM: You get in range and provoke an OA. The Orc rolls a 14. What's your AC again?
Player: 17
DM: Okay. So you move in to hit him with your blade and as you close in, he takes a swing at you and misses. Roll your attack.
Player: 16
DM: You hit. You slash his shoulder. Roll damage.
Player: 9
DM: He roars in pain, furious, as you carve a deep gash in his shoulder, your blade red with his blood.
Player: I use the rest of my movement to back up 10'
DM: You provoke another OA. The Orc rolls a 2. So he misses. In his blind rage of pain, the orc swings at nothing but air as you pull back to a safe position.
Player: I move to attack the Orc.
DM: You get in range and provoke an OA. He's got a +5. Hit a 27. And roll your attack too.
Player: 13. Plus 17 is 30. And I also roll 16.
DM: Great. You move in to hit him with your blade. As you close in, he takes a swing at you but you artfully sidestep his scimitar and answer by slashing his shoulder. Roll damage.
Player: 9
DM: He roars in pain, furious, as you carve a deep gash in his shoulder, your blade red with his blood.
Player: I use the rest of my movement to back up 10'
DM: You provoke another OA. Hit 27
Player: 19. Plus 17 is...
DM: He completely misses you. In his blind rage of pain, the orc swings at nothing but air as you pull back to a safe position.
I think the second one moves quicker. Actions and reactions can be resolved at the same time, allowing for a smoother flow.
The player is the one doing the rolls, trying to actively make a DC. It doesn't take up more time because the player can roll his dodge and his attack at the same time. The only meta information that the player "learns" about a monster is its To Hit bonus. That can be explained in-game as these characters are blooded in battle. They have enough experience in real-life combat to be able to gauge the threat an enemy poses.
That exchange has 3 attacks in it - 2 by the Orc and 1 by the player. But now the player is doing all of the active rolling and the DM is narrating. Which, when you think about, is actually closer to the DM's original role - to referee.
I'm not the biggest fan of Professor DM (I disagree on quite a few of his streamlining ideas and he veers a bit far into grognardism time and again) but on this, he seems to be spot on. Player Facing Combat (or PAR) seems to work a bit smoother, especially for larger encounters. I've got another session on Saturday and I'll have plenty of random encounters to run another battery of tests.