CR/ECL/Level Adjustments

[Johnny Angel]

I'm putting together a spreadsheet to help facilitate using the Creature Factory rules from d20 Modern (216-231) to stat out creatures. My own goal is to stat out d20 equivalents to the Star*Drive Alien Compendia, but hopefully others will find their own uses. I'd like the spreadsheet to be able to provide at least guidance to assigning CR modifiers for abilities added to the base creature. The problem is that the d20 Modern book itself doesn't give any guidelines as to how to make adjustments to a creature's Challenge Rating according to the abilities you pile on it. Looking around at other sources, there doesn't seem to be any consistent notion of how much special qualities of creatures are worth.

d20 Future, for example, has a short list of alien abilities in the Xenobiology chapter (page 212) and the suggested CR modifiers. But these CR modifiers are very different from what you get in d20 Future Tech's suggested list of robot Level Adjustments (d20FT 83-84). The Mutation Point cost for abilities that have an equivalent on the lists of mutations might be a clue, but how much of a level is a Mutation Point worth? The official WotC line would seem to be 8 MP per level using the Mutant template (d20A 42). The Future Player's Companion suggests 4 MP per ECL for abilities gained through genetic modification (FPC2 4), but then suggest what amounts to 10 MP per ECL for the same abilities assigned to a newly designed alien species (FPC 42, 43).

I don't think I'm comparing apples and oranges here. As I understand it a level is supposed to be roughly equivalent to a CR, and they should be roughly equal in power independent of whether we're talking about a template or a genmod or an inherent ability. But the answer to what a given ability is worth varies wildly in these disparate sources. Just a couple of examples:

Defense Bonus
Built-in Robot Armor (d20FT 83) - LA 1 for each +5 equipment bonus to defense
Extraterrestrial Natural Armor (d20F 212) - CR +1/3 for +3 Natural Armor bonus
Thick Hide Mutation (d20A 44) by FPC2 p. 4 rules - +2 Natural Armor bonus for 3/4 ECL
Thick Hide Mutation (d20A 44) by FPC2 pp. 42-43 rules - +2 Natural Armor bonus for 3/10 level
Thick Hide Mutation (d20A 44) by d20A 42 rules - +2 Natural Armor bonus for 3/8 level

Of course, stackability means that not all bonuses are equivalent. But even for bonuses with the Natural Armor descriptor the sources available to me give me disparate effective level values.

Damage Resistance
DR for robot heroes (d20FT 83) - 1 LA for the first 5/-, +2 for each additional 5
DR for Extraterrestrial template (d20F 212) - 1/3 CR for 5/-
Armor Plates mutation (FPC2 23) - DR 2/- for ECL +0.75 (FPC2 4), ECL +0.3 (FPC2 42, 43), LA +0.375 (FPC2 23)

Which level equivalencies should I rely on?

 

[GlassJaw]

Get Grim Tales. It has a whole section on creating your own creatures and assigning CR values for each ability.

 

[Johnny Angel]

Hmmm... According to this, they've already done a spreadsheet.

http://www.rpgnow.com/product_info.php?products_id=4035&

Not that this would necessarily make my own project moot, since it also works with a d20-ized version of the G.R.A.P.H. sytem, biochemical and environmental classes, and the metric system. But I'm glad to see somebody's covered this tricky territory.

 

[GlassJaw]

Hmmm... According to this, they've already done a spreadsheet.

http://enworld.rpgnow.com/product_info.php?products_id=4035&

Yeah, definitely pick that up. It should take care of 90+% of what you are looking for.

 

[Johnny Angel]

I picked it up, and indeed this does appear to be exactly what I needed -- indeed what the d20 system itself needed. A couple of nice points for anyone else who might be interested:

1) The spreadsheet. I'll still be making my own, but this is a damn fine one and I love the fact that the game designers have provided it.
2) It takes equipment into account. This doesn't totally solve the problem of equipment, but the d20 Modern book doesn't seem to deal at all with the fact that a 0.5 CR mook with a rocket launcher he isn't even proficient with is a lot more dangerous than a 2 CR mook with a stick he's highly trained to use. Since I use a cash system, I can use a scale similar to that of D&D to assign a certain level of gear to NPCs.
3) It's specific about a lot of the things The Creature Factory is highly vague about. A humanoid can have low-light vision for free. Without it, does the CR decrease?

I do wonder about how well the CR translates between d20 Modern and D&D, since this system is generic d20.

 

[Aussiegamer]

in reality D&D and modern are two seperate systems, even though they have compariable parts to each other.

You can not really compare them, as they do have some major differences I feel. Money being one of them thats for sure...the costs are not in any shape or form easy to change between and really require GM intervention to keep it on a even keel.

In the end the equipment is the key point...a goblin with a semi-auto pistol is far more dealy than a goblin with a short bow.

 

[Johnny Angel]

It seems as though in a system like d20 Future in which equipment is so much more important, it might be worth figuring out a way to adjust CR according to how well armed your opponents are. Perhaps you could use a system like this one we've been discussing and figure what the cost of the weapon would be if it were one of the creature's powers. That would give you an idea of the creature's power level. Of course, you wouldn't be comparing the party's actual power level in that case.

On the other hand, you could design the equipment according to some rule that would fix price according to power level and assign equipment values appropriate for each level for NPCs and PCs as they do it in D&D. I myself have such an equipment value scale that I use when equipping NPCs and new PCs, but my actual equipment prices are based on the prices listed in the Star*Drive Arms & Equipment Guide, not on any other relative power rating.

 

[Aussiegamer]

3.5 handled it.

NPC had only 1/4 of the wealth of the PC...so in effect their equipment was never as good as the players.

If they have the both have the same equipment, since it works that they were supposed to have 4 equal level encounters, then it makes sense that the CR is +4 against the opponents CR.

Equipment should not be the CR but the pilot. A CR 11 X-wing is no good in the hands of a level 1 pilot compared to a level 10 thats for sure.

 

[Johnny Angel]

So, I've been working with this Grim Tales creature creation system, and some issues have come up with regard to its compatability to d20 Modern. Conveniently, the system separates CR calculations for inherent traits of creature types from HD-dependent traits of creature types. Comparing the HD-dependent abilities listed in MM35 290 to similar data by type spread through d20M 218-224 I find no differences in the die types and BAB advancement and a couple of differences in the saving throws. The main differences between D&D and d20 Modern seem to lie in the numbers of skill points and feats given to each creature type. The D&D rules are fairly consistent -- for feats, 1 plus one per 3 HD, for skills 8 plus INT mod per HD for Outsiders, 6 for dragons and fey, 4 for intelligent undead, and 2 for everybody else. d20 Modern's Creature Factory has an eccentric list of rules to derive skill points and feats for each creature type. I've been trying to reverse-engineer the CR per HD value of creature types in Grim Tales to see if I can figure out if the values given for what is presumably based on the D&D charts is valid for the d20 Modern charts.

Note that I assume that the Grim Tales Creature Creation .pdf is referring to the D&D info because it mentions the D&D rule for number of feats (1, plus 1 per 3 HD) on page 12. Nowhere does it refer to the charts or data you need to actually assign die types, saving throws and BAB to creatures, even though these are part of the SRD for both 3.5 and Modern. It would have been handy if they had included this information and an explanation of how the system dovetailed with the one provided in the SRD.

Testing to see whether or not the CR per HD values should change between the ones apparently for D&D and the ones for d20 Modern given that the main difference is in skill points and feats, I broke the D&D data into minimum-difference pairs. So far I haven't found any consistent way to make these numbers work, especially given that intelligent constructs seem to have a lower CR per HD rating than intelligent oozes for the exact same array of HD-dependent abilities. Before, and hopefully in lieu of, banging my head against this problem for a while, I thought perhaps I could just ask the gang here:

1) Given the difference in skill points and numbers of feats between the system used in D&D and that used in d20 Modern, can the CR per HD numbers in Grim Tales be used for either?
2) If not, what adjustments should be made?
3) Why did WoTC decide to make the skill points and feats determination not only different from that in D&D, but wildly different and not even internally consistent?

 

[Flynn]

1) Given the difference in skill points and numbers of feats between the system used in D&D and that used in d20 Modern, can the CR per HD numbers in Grim Tales be used for either?
2) If not, what adjustments should be made?
3) Why did WoTC decide to make the skill points and feats determination not only different from that in D&D, but wildly different and not even internally consistent?

1. You might have to make a few minor adjustments, but truth be told, the numbers would be so small as to be insignificant.
2. If you do decide to make some adjustments, don't adjust for using the rules as written, and then modify based on bonus feats or skill points, per the rules in the supplement. (i.e. assume the baselines are equivalent).
3. D20 Modern creates monsters under the old 3E rules, instead of the more logical and highly improved v3.5 monster rules, because it was published before v3.5 came out. That's why the monster rules are the way that they are.

Personally, I've had no problems using D&D CRs with D20 Modern and Grim Tales adventures, and to be honest, Grim Tales has more in common with D20 Modern than D&D, so I think you're safe using the system as written for your conversion efforts.

With Regards,
Flynn