1e Tomb of Horrors Conversion

[Nymdok]

Originally Posted by Kuroshima

Can you outline the differences between the original ToH and the revised one? How useful will your conversion be, if I only have the revised one available?

The new one is set to a slightly lower 'Level' (9 as oppsoed to 10-14). There also appears to be more Saves versus the 'instant death' that is often found in the 1e adventure.

If all you have is the revised edition, and you understand the mechanics of that version, its a simple matter to convert using the same techniques Ive used. Its really just a matter of mapping the Damage from D&D to the Damage in GURPS. The same is true for the 'saving throws'.

Note that I didnt come up with those percentages casually. I figured what the expectation value would be for chars of a certain level and what the damage expectation would be for a given trap. Using that percentage I mapped it to 2xHP under the assumption that at -1 HP most people are largely out of the fight.

Similarly, I took the saving thorws for one of each class (F, T, MU, C) and averaged those together. Then I mapped that to a 3d6 probability and I allow the GM to decide what that success roll should be. For example, should a spring trap be a Roll vs Dodge or Per to avoid? I map the difficulty at 60% success, which is an 11 or less, and let the GM decide which is more suitable, and apply the modifiers from there.

For the record, if someone was familiar enough with the mechanics used in the revised version, Id LOVE to see a conversion done with that system and compare them. 1e books are all Ive got though :)

Nymdok

[Kuroshima]

Originally Posted by Nymdok

The new one is set to a slightly lower 'Level' (9 as oppsoed to 10-14). There also appears to be more Saves versus the 'instant death' that is often found in the 1e adventure.

If all you have is the revised edition, and you understand the mechanics of that version, its a simple matter to convert using the same techniques Ive used. Its really just a matter of mapping the Damage from D&D to the Damage in GURPS. The same is true for the 'saving throws'.

Note that I didnt come up with those percentages casually. I figured what the expectation value would be for chars of a certain level and what the damage expectation would be for a given trap. Using that percentage I mapped it to 2xHP under the assumption that at -1 HP most people are largely out of the fight.

Similarly, I took the saving thorws for one of each class (F, T, MU, C) and averaged those together. Then I mapped that to a 3d6 probability and I allow the GM to decide what that success roll should be. For example, should a spring trap be a Roll vs Dodge or Per to avoid? I map the difficulty at 60% success, which is an 11 or less, and let the GM decide which is more suitable, and apply the modifiers from there.

For the record, if someone was familiar enough with the mechanics used in the revised version, Id LOVE to see a conversion done with that system and compare them. 1e books are all Ive got though :)

Nymdok

I've played more 3rd ed than 2nd ed (and 1st ed and OD&D were before my time), so I might give it a try. The thing to consider, for a D&D 3rd ed game, is that you can gauge it for the typical 4 man party, but a bunch of heavily optimized munchkins that use whatever came in the latest book will trounce whatever you've put there.

Saves:

Let's see, at level 9, the favored saves get a +6, while the non-favored saves get a +3. You also get to add an attribute (usually between +0 and +6 at this level) and you probably have an item that gives you a bonus +1 to saves. If someone has multiclassed, or taken prestige classes, then he will have even higher saves (as per RAW). This means that the expected saves will range from +4 (Fighter, Will) to 13 (Rogue, Reflexes), that we can average at +9.

Save DCs:

A quick check shows that most saves are DC 22-23, meaning that they will be effective 45-50% of the time against a delver's maxed save, and effective 90% of the time against a delver's ignored save. In order to replicate this, I recommend that you pick the dodge, and reduce it to 9-10 via penalties, for those traps that can be dodged, and take the best will and HT, and do the same.

Skills:

A delver gets an attribute bonus (+0 to +6), plus his skill ranks (min 0, max of level+3 if it's a class skill, (Level+3)/2 if it's not) plus about a +1 gear bonus, plus maybe a +1 magical or luck bonus. Thus an optimized rogue will have 12 (Skill ranks)+6 (Dex)+2 (Gear+magic) for a total of +20. This makes most traps extremely easy to disable, at the listed DCs.

Skill DCs:

[Bruno]

For 3e DCs, I tend to roughly eyeball DC 10 as +5 to skill in GURPS, and every +2 to DC in D&D as -1 in GURPS.

The rationale is that DC 10 checks are ~50/50 for an untrained character with no attribute bonus, and +5 is a good "average" for counterbalancing a Default penalty in GURPS, bringing a stat 10 character up to ~50/50.

+2 D&D DC ~= -1 GURPS Skill/Attribute is produced by eyeballing things.

[PPoS]

I think that what Kromm has to say about this might be of help.

[Nymdok]

Ah. Let me be more clear. I have not ever played anything past BD&D and AD&D 1E. I do not understand the following terms/phrases.

DC

Save DC

Favored Save

Unfavored Save

If someone would be kind enough to outline how all this works and, more importantly what the odds of success and failure are, then the mapping is a trivial matter.

As I do not understand the terms or the mechanic, its a task Im poorly suited for.

Nymdok

[sir_pudding]

Originally Posted by Nymdok

DC

Difficulty Class. The number that you need to roll above on 1d20 to succeed.

Save DC

As above for saving throws.

Favored Save/Unfavored Save

Each class gets some saving throws bonuses at a faster rate than others.

If someone would be kind enough to outline how all this works and, more importantly what the odds of success and failure are, then the mapping is a trivial matter.

I don't think it's trivial. The philosophical differences between D&D DCs and GURPS modifiers are vast not to mention the purely mathematical differences between 1d20 and 3d6 probability.

As I do not understand the terms or the mechanic, its a task Im poorly suited for.

The 3.5 SRD is still freely available online all over the place.

[Nymdok]

Originally Posted by sir_pudding

I don't think it's trivial. The philosophical differences between D&D DCs and GURPS modifiers are vast not to mention the purely mathematical differences between 1d20 and 3d6 probability.

I'd definitely have to look into it more, but if its simple pass/fail it shouldn't be that tough.

The saving throws, for example, in 1e AD&D are flat d20. A 60% chance of success is a 60% chance of success regardless of what your rolling.

Now granted, 3d6 gets a bit coarse in the middle, but the difference between 60% and 62.5% is pretty small and overall, Id say pretty negligible.

Nymdok

[Kuroshima]

Originally Posted by Nymdok

Ah. Let me be more clear. I have not ever played anything past BD&D and AD&D 1E. I do not understand the following terms/phrases.

DC

Save DC

Favored Save

Unfavored Save

If someone would be kind enough to outline how all this works and, more importantly what the odds of success and failure are, then the mapping is a trivial matter.

As I do not understand the terms or the mechanic, its a task Im poorly suited for.

Nymdok

DC: Number you must reach with a d20+modifiers. If you have a disarm traps skill of +12, you succeed at a DC 22 check on a 10 or more.

Save DC: The number you must reach with a d20+mods to get partial or no effects from a trap, a spell, or some other nastiness. There are three types of save: reflexes (dodging out of the way, it's what you use to halve the damage of fireballs), Fortitude (Resisting an effect that targets the body directly, most often for paralysis, instant death, poisons, etc etc) and Willpower (resisting an effect that targets the mind directly). See Favored save for more details on saves

Favored save/Unfavored save: D&D 3rd ed has two save progressions, a favored, or fast one, and an unfavored, or slow one. The favored one is about twice the unfavored one. Each class gets between 0 and 3 favored saves. For example, the fighter has a favored fortitude save, and unfavored willpower and reflexes saves. To roll a save, you add your relevant attribute (Dex for Refl, Con for Fort, Wis for Will), your base save bonus (from your level) and any items that give a bonus to saves. Characters who have levels in more than one class, calculate the saves independently for each class, and add them together (So a level 4 fighter/level ranger would have +4 fort/+1 refl/+1 will from his 4 levels of fighter, and +4 fort/+4 refl/+1 will from his 4 levels of ranger, for a total of +8 fort/ +5 refl/+2 will. If he has Dex 20 (bonus of +5), Con 14 (bonus of +2) and Wis 14 (bonus of +2), his final saves will be +13 fort/+7 refl/+4 wis

[Nymdok]

Ok so lets do an example.

The First false entrance, 1. False Entrance Tunnel (page 5 of the Revised PDF) says DC 23 for 1/2 Damge, Search DC 24, Disable DC 24.

If I understand this right, then those numbers alone really mean nothing until we know the context of the party involved. I know that the module is designed for 9th level chars.

So taking the first case, Reflex save at DC 23, can you take an average of say Fighter, Magic User, Thief, and Cleric and come up with some number?

In other words, do all Fighters have unfavored reflex saves fro example? Do all 9th level fighters have the same reflex save?

Nymdok

[Edges]

Originally Posted by Kuroshima

...trounce ...

This word should never be associated with 1E Tomb of Horrors. :)