{kjd-exp} Normalizing creature XP

Hi All,

I was thinking about how 4e handles XP, which was something closer to
how 1e and 2e did it. Each creature was worth a certain amount of XP,
regardless of your level. 3e goes to some effort to maintain certain
relationships in the CR/EL calculations, and I was thinking I could
probably get away from that.


Examination of the XP tables from DMG shows that two creatures of CR n
are considered the same, for EL purposes, as a single creature of
CR n+2. The two together are worth the same XP as a single creature of
CR n+2, at all levels (after you get past the low-level odd behavior in
the table).

XP for a single creature is equal to its CR * 300, when encountered at a
level equal to its CR. It gets increased or decreased from there,
depending on the level at which it was encountered. Lower-level
creatures are worth less, higher-level creatures are worth more.

3e rules have the amount of XP needed to gain the next level directly
proportional to the current level. This leads to the manipulation
mentioned above, where the designers tried to keep the XP gained for
each creature linearly proportional at the appropriate level, but
maintain an exponential growth in power.

If we want to get rid of this, but maintain advancement comparable to
current rules, we would need to make all XP values (per creature and
needed to level) exponentially proportional to the level involved.

Thankfully, this isn't very hard. If we multiply the XP value at each
level by sqrt(2), we keep the "n+2 = 2*n" behavior exhibited in 3e.

Assuming, for the sake of argument, that the base XP value for a
creature is 100 XP (scaling exponentially afterward), at every level it
would take the XP gained from 10 creatures of the same CR to advance one
level. Creatures from lower levels gain you less XP (it would take
twice as many creatures of CR n-2, as it does now in 3e); creatures
from higher levels gain you more XP (twice as much for a creature of
CR n+2 as a creature of CR n).

This results in a somewhat funkier table than the current one (XP for
each level = 1000 * sum( 0..level-1)), but you no longer have to look up
the XP for monsters that are of different CR than the current level.

As with 4e, this lets you build a 'balanced encounter' by getting
together a number of monsters whose XP add up to about the level you
want. A level 5 encounter might therefore have about 400 XP worth of
creatures 'per party member'. Ten such encounters means the party
levels.

As an aside, similar logic can be used with 3e -- add up the XP of the
CRs of the monsters involved to get an encounter of EL = target CR.
You have to use the XP table more, though. I'd as soon have this
table, and decide how many XP I'd like my players to (potentially) get
through a particular encounter.


Level XP to next XP total Approximation Difference
1 1,000 0 0
2 1,414 1,000 1,000 1,000
3 2,000 2,414 2,400 1,400
4 2,828 4,414 4,400 2,000
5 4,000 7,242 7,200 2,800
6 5,656 11,242 11,200 4,000
7 8,000 16,899 16,900 5,700
8 11,313 24,899 24,900 8,000
9 16,000 36,213 36,200 11,300
10 22,627 52,213 52,200 16,000
11 32,000 74,840 74,800 22,600
12 45,254 106,840 107,800 32,000
13 64,000 152,095 152,000 45,200
14 90,509 216,095 216,000 64,000
15 128,000 306,605 307,000 91,000
16 181,019 434,605 435,000 128,000
17 256,000 615,624 616,000 181,000
18 362,038 871,624 872,000 256,000
19 512,000 1,233,663 1,234,000 362,000
20 732,076 1,745,663 1,746,000 512,000

First column is character level.
Second column is XP needed to advance to the next level.
Third column is the total XP gained by the character.
Fourth column is an approximation to a rounder number.
Fifth column is the difference between approximations.

All in all, the approximations look like decent numbers, and the
differences show a pretty close match to the raw numbers needed to
advance.


Thoughts, questions, comments?


Keith
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Keith Davies wrote:

> Thoughts, questions, comments?

When will we be free again?

Also, you've got level 1 wrong. CR under 4 adds linearly up to 4
(well, the CR 2-4 range overlaps, but everything under CR 2 is linear
only). That'll mess with your approximations and such too.

Doesn't really matter, after all, what's 300 XP between friends?
Still, I can't resist playing with pointless things like this.


Level total XP XP by CR
1 0 60
2 200 120
3 600 180
4 1,200 240
5 2,000 330
6 3,100 480
7 4,700 690
8 7,000 900
9 10,000 1,500
10 15,000 1,800
11 21,000 2,850
12 30,500 3,750
13 43,000 5,700
14 62,000 7,500
15 87,000 11,400
16 125,000 15,000
17 175,000 22,500
18 250,000 30,000
19 350,000 45,000
20 500,000 60,000
21 700,000 90,000

Numbers matched neatly to usual 40 encouters per 3 levels standard.
20,000 XP to cast /Wish/ and 300 XP to cast /Limited Wish/, give or take
a bit depending on how you're measuring.
Feel free to multiply it all by 5 again, but it just makes it
messier. Can divide by 5 again and stay tidy, but XP for very low CR
monsters starts to get messy. <shrug>

You can even redo item costs and wealth per level so you normally
match 5gp to 1 XP with that. If you're keen. I've got the adjusted cost
formulas somewhere, but it's fairly straitfoward.

--
tussock

I'm like a box of chocolates; you never know what you're gunna get.