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Eldan
2011-10-18, 06:39 AM
This came from a discussion in an earlier thread about how damage reduction didn't really scale with level, and how high it should be to still remain relevant. Percentage-based damage reduction was brought up, e.g. damage reduction that reduces all damage by X%.
So, my suggestion is this:

Damage Reduction X/[material]

The X in damage reduction X means the following: Damage reduction reduces all bludgeoning, slashing and piercing damage that is not from [material] by 1 point, plus another point for each X points of damage dealt.
As a simple conversion for monsters, I suggest:
DR 5/X: Becomes DR 10/X.
DR 10/X: becomes DR 5/X.
DR 15/X: becomes DR 3/X.

Example 1:
The Iron Golem has DR 15/adamantine in the normal rules. Here, this turns into DR 3/adamantine.

Jack the Fighter hits the iron golem for 30 damage with his greatsword. Damage reduction prevents 1 damage, plus another 30/3=10 damage, for a total of 11 damage prevented, or 19 damage dealt.
His party colleague, Bob the Rogue, deals 7 damage with his shortsword.
Damage reduction prevents 1 damage, plus another 7/3=2 damage (rounded down), for a total of 3 damage prevented, or 4 damage dealt.

Example 2:
The Dretch has DR 5/cold iron or good in the old system. In the new system, it would have DR 10/X.

Jack the Fighter, again, deals 30 damage with his greatsword. Damage reduction prevents 1 damage, plus another 30/10=3 damage, for a total of 4 damage prevented, or 26 damage dealt.
Bob the Rogue, again, deals 7 damage with his shortsword.
Damage reduction prevents 1 damage, plus another 7/10=0 damage (rounded down), for a total of 1 damage prevented, or 6 damage dealt.

Effect?
Notably, at low levels, DR will not be as strong. Perhaps level scaling would have to be introduced again in the conversion, I'm not quite sure. People dealing smaller amounts of damage several times, e.g. TWF-combatants dealing four times 1d6+3 damage, still have a chance to hit these fighters, while the reduction doesn't become entirely pointless against people dealing hundreds of damage per attack.

Thoughts?

lesser_minion
2011-10-18, 08:39 AM
The problem here is that while you've mitigated the balance issue of DR that applies on a per-hit basis, you've also taken away its ability to actually do its job (provide a balanced way to handle creatures whose legends imply that they are nigh invulnerable with the exception of certain weaknesses).

I think the simplest way might be to separate DR out into two components: an AC bonus that goes away against certain attacks, and an 'imperviousness' value, that negates a certain amount of damage per encounter.

The whole mess should probably be considered supernatural, since apart from the adamantine thing, it actually is magic.

Objects would remain problematic, but I believe they'd need work either way.

Yitzi
2011-10-18, 08:54 AM
The problem is that then DR overscales with level, as it's a percentage that keeps increasing.

To see how ridiculous it can get, consider an epic creature with DR 50/-. Extending your rules, DR 50 would presumably become DR 1, so DR 50/- would mean complete immunity to any damage subject to DR.

I'd say that if applying this rule (and it is indeed absolutely necessary in rocket-tag play), DR should be made much more even and not increase with level (probably 2 for most creatures, 1.5 for creatures with high DR for their level, and 3 for creatures with low DR for their level. Adamantine armor should probably be 4 for heavy, 6 for medium, and 8 for light.)

Eldan
2011-10-18, 09:01 AM
In a short, and certainly not comprehensive overview of epic monsters, I haven't found anything above 20, actually (the epic golems and colossi).

But yeah. This needs a DR/level table, of what is considered low, medium and high at each level.

As a rough guide:
Low: DR<CR-5
Medium: DR=CR+/-5
High: DR>CR+5

Though that, again, gives no creature an actual high DR at high levels. But then, DR 20 on epic is really, quite a bit laughable.

T.G. Oskar
2011-10-18, 10:38 AM
I believe there's a simpler and properly scaling method of damage reduction by percentage, although you might need a calculator (though there are some cheats towards it).

Basically: every point of damage reduction reduces 5% of the damage, up to a total of 95% (at DR 19), up to a minimum of the indicated number. Thus, for example, a DR of 10/- would reduce 50% of all damage, to a minimum of 10 points. Existing DR scores would remain as intended, except that there would be tops: DR 20 would be the maximum DR (reduce 95% of damage, to a minimum of 20 points) while DR X/- (unbeatable DR) would have a minimum of 10 (so you can only reduce half damage through unbeatable DR).

The most complicated part would be to determine the exact reductions, but you can easily figure that DR 5 reduces 25% (so one-quarter of the damage), DR 10 reduces half damage, DR 15 reduces three-quarters of damage, and every 2 points of damage is a one-tenth reduction, so that covers nearly everything. Couple that with "every point of DR reduces damage by half of one-tenth" (reduce damage by one-tenth, then by half that) and you shouldn't have too many troubles doing the mnemonics for it (if that's the concern; otherwise use a calculator).

I've tried it at my own table, and while it hasn't made a clear difference (because DR amounts are low), it does work for characters that deal absurd amounts of damage, while not penalizing entirely those that deal little. It's still a challenge how to deal with those characters that deal multiple attacks, which tend to suffer a bit more until they reach a threshold.

Eldan
2011-10-18, 12:30 PM
Hmm. 95% sounds, honestly, pretty high. I wouldn't go above perhaps 75% or so, and that's already pretty extreme.

Yitzi
2011-10-18, 10:54 PM
In a short, and certainly not comprehensive overview of epic monsters, I haven't found anything above 20, actually (the epic golems and colossi).

True, so I suppose that's not such a big concern unless this is to be used with homebrews. Still, it scales poorly.

T.G. Oskar
2011-10-19, 12:09 AM
Hmm. 95% sounds, honestly, pretty high. I wouldn't go above perhaps 75% or so, and that's already pretty extreme.

True, but it allows for a reasonable progression. While not the same scaling as BAB, or saves, it is the same effective increase you gain when you get a +1 to attack rolls or saving throws. I left it at 95% so that reaching DR 20 didn't became instant immunity to damage, but I can figure there might be a concern about damage top.

Still; do consider that the proposal has a way to reduce the percentage top added in. If you were to aim at 75%, you could achieve that top at DR 15, with higher amounts of DR applying only to the minimum reduced damage. You could easily say that the top is 50%, and every 2 points of damage reduction involve a 5% reduction, but the lower maximum would be insanely weak (5 points reduced from 100 points of damage still leaves 95 points of damage, which is a lot). You could tweak the boundaries for both lower and higher maximum reduction, but you'd have to work a different way of progressing the reduction percentages. A 5% increase per point of DR is simple, and easy to work in terms of mnemonics, if a bit slow: with some effort you can find the half of a number, and the tenth of a number; the half of the tenth of the number would be 5%, and multiplying that by the damage reduction would give you the actual reduction. Now, if you're working on a calculator, any kind of percentage will be calculated easily, so you can define your boundaries and your steps closer to what you want; the proposed idea was to make it as easy as possible for mental calculations (as odd as that sounds), and considering how the Monster Manual organizes DR neatly into DR 1-5, DR 10, DR 15 and DR 20 (with some rare moments where DR might be 8 or something), your job is made relatively easier. The problem, as you mentioned, would be the extreme variance (from a pitiful 5% to an extreme 95%) of the percentages, but that's easier to fix.

In simpler terms; it's to give you an idea of how to progress based on percentages. The actual top is merely a recommendation, which you could easily alter to suit your needs.

Ashtagon
2011-10-19, 01:49 AM
My approach was simpler...

If you have DR 10-19, any damage received will be divided by 2 or reduced by your DR, whichever gives the lower result.
If you have DR 20-29, any damage received will be divided by 3 or reduced by your DR, whichever gives the lower result.
If you have DR 30-39, any damage received will be divided by 4 or reduced by your DR, whichever gives the lower result.

Notes:

The pattern would continue for higher DRs, but such high DR numbers are not canon.
This rule also applies to energy resistance.

Eldan
2011-10-19, 06:52 AM
After looking at it a bit more, I think I'll go with:

DR is lower than 1/2 CR: low (1/10 damage prevented)
DR is equal to or more than 1/2 CR, but less than CR: medium (1/5 damage prevented)
DR is equal to CR or higher: high (1/2 damage prevented)

Or:
{table=head]CR | Low | Medium | High
1 | - | - | 1+
2|-|1|2+
3|1|2|3+
4|1|2-3|4+
5|1-2|3-4|5+
6|1-2|3-5|6+
7|1-3|4-6|7+
8|1-3|4-7|8+
9|1-4|5-8|9+
10|1-4|5-9|10+
11|1-5|6-10|11+
12|1-5|6-11|12+
13|1-6|7-12|13+
14|1-6|7-13|14+
15|1-7|8-14|15+
16|1-7|9-15|16+
17|1-8|9-16|17+
18|1-8|9-17|18+
19|1-9|10-18|19+
20|1-9|10-19|20+
[/table]

That should scale nicely, though on high levels, high DR is rare.