Adjusted DN vs Difficulty Modifiers

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Adjusted DN vs Difficulty Modifiers

Postby greybird » Fri Nov 01, 2019 1:13 am

What's the low-down on the difference, mechanically between the two? When do I, as the GM, choose one over the other? Believe it or not, I've had the hardest time wrapping my head around this.

For instance, if a player wants to do something that I judge to be 'hard', when would I give them a DN 10 with a -4, and when would I give them a DN 14?

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Re: Adjusted DN vs Difficulty Modifiers

Postby Count Thalim » Fri Nov 01, 2019 3:24 am

I tend to stick with DN targets, except when I have thrown other complicating matters in.

I.E you want to jump from one ledge to another in driving rain. Do I apply a DN 14 or a DN 10 with a -4 penalty for the driving rain?
Depends if I want that driving rain to be a factor elsewhere. Like they are shooting at the fleeing bad guy at the same time. In that case it is easier to just put down a -4 situational penalty on their rolls than mess about with individual TNs, especially where things like Dodge are already fixed.
Similar to have we have darkness penalties.

It also allows me to tilt the playing field slightly based on my players. If I know someone has taken a perk that allows them to negate penalties I will try and build those in so they are able to use their perk. You can't do that with a straight DN number.
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Re: Adjusted DN vs Difficulty Modifiers

Postby Kuildeous » Fri Nov 01, 2019 9:26 am

Numerically, over 99% of the time, the two are equivalent. It’s a little less mathy for the player to adjust the DN on your end. If you simply tell the player they need a 14, then the player doesn’t need to worry about subtracting 4 from their roll, especially if they tack on a bunch of other modifiers.

As Thalim says, there are some things that can negate penalties. So here’s where that < 1% comes in. It might be important if it’s a DN increase or a penalty.

My rule of thumb, should that come up, is that the DN is adjusted according to the base scenario. For example, I might give these DNs:
DN 10: Hopping down a 6-foot drop without injury.
DN 12: Safely leaping over a chasm.
DN 18: Jumping from the roof of a 23-story building onto a 20-story building across a 6-lane road.

In all those cases, I would treat those as the base difficulties. They don’t have penalties; that’s just how difficult they are.

Now if I throw in some rain, that could impose a -2 penalty. Sure, I could say that hopping down from a 6-foot drop in the rain is DN 12, but technically it’s more correct to say it’s DN 10 with a -2 penalty, which could be important for some rules.

And they could be combined, though I find I often don’t need to. If someone is leaping over a chasm in the rain, then I could say it’s DN 12 with -2, but I’m more likely to simply say it’s DN 14. If a player calls me on that and says they have a means to negate penalties, I’ll say that it’s actually DN 12 since part of that is from rain.

That’s how I view it. If it’s part of the environment, it’s DN adjustment. If it’s an external factor that could be negated by cyberware, magic, or a perk, then it’s probably a penalty.
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Re: Adjusted DN vs Difficulty Modifiers

Postby greybird » Fri Nov 01, 2019 11:42 am

Ok, thanks. Here's my takeaway.

DN represents the natural difficulty of the task without any external factors, while the modifiers just represent external, changing factors.

DN can differ mechanically from modifiers, as there are rules that allow players to alter modifiers, but not DNs. For example, a DN 14 task and a DN 10 task with a -4 mod are mathematically identical, but performing a standard task in the dark (DN 10 with a -4) is affected by abilities like Darkvision ("ignore 4 points of darkness penalties") while setting the DN to 14 effectively takes away the advantage that character has.

It is also harder to communicate to the player exactly what's going on when you just toss them a DN 14, versus telling them they have a -4 darkness penalty. That makes it harder for players to know when their abilities and options kick in.

So, again, thanks. It's one thing to know the rules of a system, but I really like to sit down at the table with an understanding of they whys and wherefores behind those rules. It makes it easier to work with them, and makes me less likely to inadvertently blind a dwarf.

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Re: Adjusted DN vs Difficulty Modifiers

Postby utsukushi » Fri Nov 01, 2019 12:23 pm

I think the other element (which is totally encapsulated in what's already been said, but I didn't see explicitly) is precedence. Having your players roll DN 10 with a -2 rain penalty tells them that hopping down a 6' ledge is going to be 10 in the future, where if you just give them the 12 that's unclear.

But that's still basically a matter of communication. It wouldn't hurt much if you said, "It's a 12 because of the rain, but normally a drop like this would be 10." And that also does open them up to say things like, "But wouldn't my GadgeTech Auto Umbrella Mk IV help?" And then you can say, "Oh, yes, of course, Inspector. As the umbrella unfolds from your head, you'll only need a 10."

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Re: Adjusted DN vs Difficulty Modifiers

Postby ZorValachan » Fri Nov 01, 2019 9:21 pm

I use roll20 a lot. there the character sheets, while in theory able to add bonuses/penalties to the die roll, are much easier to adjust the DN. So normally, as the GM I would go ok, he has a 12 dodge, but is vulnerable, so that makes it a 10, but rain cancels that so it's a 12. The player says, I have cybereyes (or whatever) which removes -2 penalties - ok back at a 10. Push the button to roll, put in 10 and see the result.

My modified sheet is adding buttons for bonuses and stymies. and while technically vulnerable gives opponents a +2 against them, lowering all DNs/Defenses, by 2 means the players don't have to remember (even with symbols they forget), and can just worry about their side.

no matter what, there isn't a difference to the result needed. if I need to have a total of 14 for a DN 14 or a total of 14 for a DN of 10 because i have a -4 penalty, my total in either case needs to be a 14. if the math is done correctly, it simple doesn't matter. Although mentally it might be easier for some to put it on one side or the other (like I said, i tend to view vulnerable as affecting the vulnerable person lowering defenses) other people might see if differently.
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