Using D20 Modern for T20: The Wall

tjoneslo · Aug 24, 2005

While working on the project in my spare time, I found that I've smacked into four wall at the same time. In no partiular order:

1. I can't publish this. At least not with the Traveller name on it. The owner of this site has the licence for the D20 version of Traveller. And he won't give it up lightly, not unless I have some form of bribe...

2. Irreconcilable differences over the combat system. How do hit points work? Keep the level based defense bonuses? Autofire and sniping? Vehicle and starship combat? There are things I don't like about either system, but simply shoving the two together won't fix either one. Meaning I need a complete set of rules, which requires playtesting, and revisions and ...

3. An inability to remain focused. I just got a copy of the Spycraft v1.0 book for really cheap. And it has a whole bunch of cool ideas (and some I really don't like). But the more ideas I incorporate from outside of D20 modern, the further it gets from the core rule book. So at what point do I acknowledge that I'm no longer a giving a few simple variations on the D20 Modern system but really writing a D20 OGL SF rules book. For Traveller. Except it can't be for Traveller...

4. I'm unimaginative. I realized none of the new rules in this book I've come up with. They're all someone elses rules tweaked to be consistent. Brilliant game designer I'm not. I've never been much of a fan of other rule-puree attempts. It usually comes out pretty bland and uninspired. Sometime you can hide this under a good bit of writing, another skill which I lack.

In any case, I'm going to put this project down for a while until something else inspires me to overlook my shortcomings.

stofsk · Aug 24, 2005

Why not just treat it like a set of alternate house rules? There's like a site for that, called freelance traveller or something.

For what it's worth I have a similar problem with a campaign setting I'm developing, in that I use the T20 rules along with a couple others (SW D20) while changing this and that for a different 'feel'.

mike wightman · Aug 24, 2005

hmmm...

1. call it D20 Future Traveler

(just kidding)

2. use vitality/wounds - they are OGL now - keep the level defence bonus, use D20M for autofire and sniping.
Write your own vehicle and starship rules - D20 M/F has been crying out for a decent set IMHO.

3. Spycraft vehicle chase rules have found their way into other games...

4. don't sell yourself short - there have been lots of great bits in these threads of yours over the past few months.

Kirth · Aug 24, 2005

Don't feel bad tjoneslo, I try and shoehorn the two together and get frustrated. Plus, I just started a new job, so I haven't even looked at the material you posted.

Anyway, your work is appreciated and has given me plenty of ideas for the future(no pun intended).

tjoneslo · Aug 24, 2005

OK, enough ego-stroking the author.

Problem 1 with simply posting it. The rules will end up being about 100+ page PDF. Even without including the OGL rules from the SRD and the T20 book. Including the stuff may push it to 200+ pages. This is the downside to the D20 rules. You can't publish a set of rules in anything less than 150 pages. Makes me long for the days of CT....

I could also, in theory, post it here in the fLibrary. Assuming the librarian is still accepting submissions.

I think I'm going to use the T20 Lifeblood/Stamina system, but use the D20M DR for armor system. This means I can use the D20M weapons, which are not quite as high powered as the T20 ones. But it does mean the armor values will be higher too.

All right. Back to work then.

Qstor2 · Feb 21, 2006

Originally posted by tjoneslo:
2. Irreconcilable differences over the combat system. How do hit points work? Keep the level based defense bonuses? Autofire and sniping? Vehicle and starship combat? There are things I don't like about either system, but simply shoving the two together won't fix either one. Meaning I need a complete set of rules, which requires playtesting, and revisions and ...

3. But the more ideas I incorporate from outside of D20 modern, the further it gets from the core rule book. So at what point do I acknowledge that I'm no longer a giving a few simple variations on the D20 Modern system but really writing a D20 OGL SF rules book. For Traveller. Except it can't be for Traveller...

I think the HP/Massive damage rules of D20 Modern would work well with Traveller. Most D20 Modern classes might have problems making the DC 15 Fort Save. As the other poster mentioned Wounds/Vitality seem to work well too and IMHO aren't noticiably different from T20 rules.

Auto fire..keep the feats for d20 Modern on the issue? Sniping? Readied actions in d20 seem to work at least IMO....

Starships/Starship combat is the big stickler IMHO. The systems seem two different to me. A poster in another thread mentioned junk one or the other...

Mike

mike wightman · Feb 21, 2006

Starships/Starship combat would probably benefit from being re-thought out.

Starship combat in d20M/F is not very good IMHO, but at least conforms to the D20 methods of doing things.

T20 does an excellent job of providing stuff for the PCs to do, but I think is hamstrung by being based off High Guard USP factors.

mike wightman · Feb 21, 2006

As for HP/massive damage, just add the tweak that failure of the fortitude save leads to bleeding to death...
lose 1d4-1d12HP per round until unconscious etc.

tjoneslo · Feb 21, 2006

Re: Hit points. I wanted to keep the Lifeblood/stamina system mostly because I like the deadly nature of Traveller combat. It does so without adding any dice rolls, and without adding any unexpected "you die" moments.

There are many tweaks for the HP/Massive damage rules. I'm thinking of simply listing all of them and telling the GM to pick one (with some advice). The items I have now are:

Damage Threshold: How much damage triggers the damage threshold:

- 
- Fixed value between 5 and 20.
- Characters Con (with modifier(s))
Save DC: What is the save DC to avoid the massive damave effect.

- Fixed value between 10 and 25 (default is 15).
- Based upon damage
Effect of failing the save:

- Character dies (-10 hp)
- Character is rendered unconcious (0 hp)
- Character takes additional damage. (based on degree of failure?)
What effect do critical hits have on the massive damage rules?

mike wightman · Feb 22, 2006

Damage threshold - I'd go for Con

Save DC - equal to damage done

Failed save - lose a number of hp every turn until bleeding is stopped or eventual death

Critical hits - more likely to trigger massive damage effects

Will armour provide a bonus to AC, damage reduction, or a bit of both?

archhealer · Feb 23, 2006

In all my D20 games, in any context, I use a makeshift crit table similiar to the old I.C.E. games, with seperate tables for ballistic, piercing, slashing, crush, etc. damage types. A little bulky, and frequently I just wing it, but I like the detail. Oh, and other than the standard weapon DMG multipliers for crits, I don't add damage effects, but add other neat effects (Temporary ability damage, character knocked prone, stunned, shaken, etc.)

TheBrain · Feb 25, 2006

Originally posted by Archhealer:
In all my D20 games, in any context, I use a makeshift crit table similiar to the old I.C.E. games, with seperate tables for ballistic, piercing, slashing, crush, etc. damage types.

GASP! Not "Chartmaster"! Oh I remember those things. Still some of the little descrptions were amusing.

Reginald · May 7, 2006

Originally posted by Sigg Oddra:

Starship combat in d20M/F is not very good IMHO, but at least conforms to the D20 methods of doing things.

d20 Future starship combat treats it similar to character combat, which is different from d20 Modern vehicle combat rules that includes facing. Personally, I'd rather the Future designers conform to the already established vehicle combat rules in d20 Modern.

Reginald · May 7, 2006

Originally posted by tjoneslo:

There are many tweaks for the HP/Massive damage rules. I'm thinking of simply listing all of them and telling the GM to pick one (with some advice). The items I have now are:


Damage Threshold: How much damage triggers the
damage threshold:



Fixed value between 5 and 20.

Characters Con (with modifier(s))

Character's Con (default Heroic d20 Modern Reality Level)
Fixed value = 10 (Realistic Reality Level; first used in Call of Cthulhu d20 RPG)

Personally, I'd go with MDT (or massive damage threshold) 10.

Save DC: What is the save DC to avoid the massive damave effect.




Fixed value between 10 and 25 (default is 15).

Based upon damage

Personally, DC 15 is fine. Feats like Improved Autofire (from Ultramodern Firearms d20) could always raise DC to 20.

Effect of failing the save:




Character dies (-10 hp)

Character is rendered unconcious (0 hp)

Character takes additional damage. (based on degree of failure?)

If lethal/normal damage inflicted, a failed save would drop character's hit point to -1 and is now dying.

If nonlethal damage inflicted, a failed save merely renders character unconscious at 0 hp.

Either way, he automatically drops.

What effect do critical hits have on the massive damage rules?

None, AFAIK, other than compare the total damage value -- whether it is normal or a much larger critical hit -- to the character's MDT. Most likely, a critical hit damage (if greater than character's MDT) will force the affected character to make a Fort save or he drops. Aside from that, if his current HP is less than the critical hit damage, then he automatically drops dead (or dying if it hasn't reached -10 HP).

OBTW, I'm not a fan of the existing d20 Modern nonlethal damage rules. I revert to using D&D 3.5e nonlethal damage rules.

Reginald · May 7, 2006

Of course, if IIRC, Hunter did want to use VP/WP system but at the time he was developing T20 it was off-limit.

Until now. You can find the VP/WP health system in Unearthed Arcana, one of a handful of books published by WotC to include Open Game Content with OGL attached to it.

(Don't bother to ask whether they will put it in the SRD. Because it is already designed OGC in that book, there is no need to go the extra step. It's not like we'll see a Traveller SRD anytime soon.)

Oh, and don't plug-n-play the health system "as is." Personally, I would add the death's door rules (i.e., the -1 to -10 HP).

tjoneslo · May 8, 2006

As one Traveller fan pointed out: A shotgun does 3d6 damage. A character has 3d6 hit points. There is a beautiful symmetry there.

This is deliberate. Hunter and Martin wanted this symmetry. And it was appreciated by the Traveller fans.

If the D20 Future Traveller rules are going to be Traveller in any sense of the word, I must maintain this symmetry (and relative combat deadliness). The WP/VP system does not maintain this deadly nature, and the Massive Damage rules might but it requres statistical analysis to prove it.

Reginald · May 8, 2006

Sorry, I'm not good on statistical analysis... But I'd like to see such results on d20 Modern HP system using two of the Reality Levels (Con score vs. 10).

Actually, Ultramodern Firearms d20 author (and d20 Modern co-designer) suggested that if one were to use VP/WP system instead of the d20 Modern HP system, to increase all firearms damage by one die.

Granted, this doesn't make it any dangerous since VP/WP does not force the victim to roll a Fort Save or drop, any damage to WP (which is equal to Con score) would automatically penalize the victim due to suffering a fatigued condition (he rolls Fort save or pass out). Also, if a shotgun does 4d6 (one more die of damage) to a 3d6 character (assuming his Con is 18; therefore his WP is 18), on a good critical hit, he'd drops.

tjoneslo · May 8, 2006

Hrm, Statisical analysis on D20 is more complicated than any other game system, mostly because of the Feats creating so many exceptions to the base rules. The goal here is we want the average gun shot to take down an average character about 50% of the time.

We will use three guys: Mook (Con 10), Bob (Con 13) and Al (Con 16). The Mook also serves as the fixed MD check.

From the D20 modern SRD, most handguns do 2d6 damage, (average 7 points), not enough to provoke a MD roll. Bob and Al are immune to MD damage from handguns, and Mook requires one 8% of the time (11 or 12 pts damage).

Many of the longarms do 2d8 damage(avg 9 points), not enough to provoke a MD roll. Al is immune to longarm MD damage. Bob needs to make a Massive damage roll 9% of the time. Mook needs a MD roll 32% of the time.

Some of the longarms do 2d10 damage (average 11 points). Al needs a MD roll 10% of the time, Bob rolls MD 28% of the time, and Mook rolls it 55% of the time.

Critial hits, which occur 5% of the time, doubles the damage done. In our analysis, this increases the percent of the times our three friends need to make MD rolls.

<blockquote>code:<hr /><pre style="font-size:x-small; font-family: monospace;">Person 2d6 2d8 2d10
Mook 11% 36% 60%
Bob 3% 12% 32%
Al 0% 3% 17%</pre>[/QUOTE]This is just the percentage change of invoking the Massive Damage check. The check itself is a Fort save vs. DC 15. At first level, characters fail this check 75% of the time. At 10th level this has fallen to 50%-60%, perhaps lower from feat choices.

The T20 prior history generates (and game adventures assume) characters between 7th and 12th level. We'll assume 7th level characters here, which gives a maximum of 65% failure rate. Factoring this in to the table above gives:

<blockquote>code:<hr /><pre style="font-size:x-small; font-family: monospace;">Person 2d6 2d8 2d10
Mook 7% 23% 39%
Bob 2% 8% 21%
Al 0% 2% 11%</pre>[/QUOTE]The table gives the percent chance a single shot will render the target at 0 hp. This falls far short of the 50% kill rate the T20 system gives for shotguns.

tjoneslo · May 9, 2006

And the second table is wrong. I forgot to include the constitution modifier to the Fort save.

<blockquote>code:<hr /><pre style="font-size:x-small; font-family: monospace;">Person 2d6 2d8 2d10
Mook 7% 23% 39%
Bob 2% 7% 13%
Al 0% 1% 7%</pre>[/QUOTE]What this means is if we want the Massive Damage throw rules to reflect the desired 50% kill rate we would need to make the fixed value very low. So low you can hardly call it "massive" damage any more. In fact, to make this work it might be best to dispose of the damage roll all together and use a simple damage save. Like used in Blue Rose, True20, or Mutants and Masterminds.

mike wightman · May 10, 2006

What if the fortitude save is made a bit more difficult?

DC = 5 + rolled damage

or

DC = 10 + rolled damage

Or have the amount of damage modify the saving throw.

Using D20 Modern for T20: The Wall

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