Time Travel

[Roudi]

I'm getting ideas together to make it easier to run campaigns involving time travel in small or large amounts. I think there's a lot of mechanical ground that needs to be covered in the d20 Modern system to meet all the needs of players and GMs (or at least most of their needs). Mechanics for things like causality, the effects of different technology levels against each other, and others need to be addressed. I'm also looking to compile as many different kinds of time travel as possible to give GMs ideas.

These quick and dirty rules were suggested by Ymdar (who himself was helped by sinmissing). I've taken them and adapted them slightly. I want to get some opinions on these if possible.


When PLs Collide
With time travel, there may come a point where a group of modern adventurers are confronted by a group of high-tech thugs from the future. Similarily, those same adventurers may be beset by a pack of cro-magnon savages. How do the PC's weapons and armor faire against those of different progress levels? These mechanics should help.

Higher PL weapon against lower PL armor
If the attacker's weapon is a higher progress level than the protection worn by the person being attacked, odds are that the protection in question wasn't designed to protect against that kind of weapon. The attacker gets a +1 bonus on his attack for each Progress Level his weapon is above the armor of the defender. This attack bonus may be no higher than the equipment bonus to defense granted by the armor, minus the armor's nonproficiency bonus.

Example: Charlie fires his Plasma Rifle (PL 7) on Jericho, who is wearing a simple Undercover Vest (PL 5). Because Charlie's Plasma Rifle is two PL's higher than Jericho's armor, Charlie gets a +2 bonus on his attack.

Example: Charlie fires his Plasma Rifle (PL 7) on Jenny, who is weaing a Light Undercover Shirt (PL 5). Charlie would normally get a +2 bonus on his attack, but Jenny's Vest provides an equipment bonus of +2 and a nonprof. bonus of +1. Thus, Charlie only gets a +1 bonus on his attack roll against Jenny.


Higher PL armor against lower PL weapon
In most cases, greater technological advancements mean better protective armor. If an attacker has a weapon that is a lower Progress Level that the armor worn by the defender, odds are that armor will offer better protection. For each Progress level above the attacker's weapon, the armor is considered to have two points of Damage Reduction.

Example: Jericho whips out his Beretta 92F (PL 5) and fires on Charlie, who is wearing a Medium Combat Suit (PL 7). Charlie enjoys DR 4/- in addition to the bonuses prodived by his armor against Jericho's "archaic" weaponry.


All right, there are the basics. Here are a couple of gadgets to keep PCs from always hunting after the highest-PL technology they can scavenge...

Advanced Construction (universal)
The object is composed of more technologically-advanced materials. Choose a higher Progress Level than that of the object. The object is now treated as an object from that Progress Level.
Purchase DC mod: The difference between the object’s new PL and it’s former PL.

Old-Fashioned Construction (universal)
The object is built in a very archaic matter or makes use of really old technology. Choose a lower Progress Level than that of the object. The object is now treated as an object from that Progress Level. The GM should use discretion to determine if the lower PL is infeasable for type of object (like a PL 7 Plasma Rifle designed with PL 3 technology).
Purchase DC mod: None.

A reminder about Purchase DCs and Progress Levels: You can buy objects of a lower PL for -2 less Purchase DC. If you're playing in Progress Level 8, and buy a Falcon .45 (a PL 5 weapon) with the Advanced Construction gadget to make it a PL 8 weapon, then the Falcon costs it's regular Purchase DC +3. Regularly, in a PL 8 setting, the Falcon would cost it's normal Purchase DC -6. See how it works? Same rules apply to Old-Fashioned Construction... a Falcon .45 constructed using PL 4 tech costs 2 less.

 

[Buddha the DM]

Interesting ideas that you have here so far. Do you have anything else?

 

[Aussiegamer]

He might have but he will not tell you ( )

I think that the whole PL higher v lower is a bit of a waste as it is basically already taken into account. The higher PL weapons do more damage and the higher PL armour is better to use.

So adding in a +1 bonus per difference seems a bit unfair.


Why would something older than the PL you are at be cheaper? Lack of mass production and parts will keep the DC higher.

Look at antiques today, they are more expensive than they were when they wer made.

Imagine a PC looking for bullets for his pistol in a high PL plamsa gun world. No chance to buy them over the counter and he would have to get them hand made. So the price would be very high.

IMHO

 

[Roudi]

Unless the armor grants DR, then all weapons deal the same amount or damage to a character be she armored or unarmored. However, as the rules stand, any given piece of armor is just as effective protection against a weapon from the stone age or a weapon from the fusion age. Also, higher PLs do not always translate into higher Defense bonuses for armor. Do you really think Full Plate Mail should deflect a laser bolt or a railgun blast as effectively as it turns a sword? Do you really think a musket should be as effective against Land Warrior armor as it is against samurai armor?

These rules are, of course, optional... I'm presenting them here for anyone who feels that inconsistencies like those I've stated above shouldn't happen in their time-hopping d20 games. As for them being unfair... yeah, they are. If you take a railgun from the future and go back to the Crusades I DO expect that railgun to do better than the weapons of the time. Not just in terms of damage, but in its ability to bypass protection. Time travel MAKES THINGS UNFAIR in that sense. Does it remove challenges from the players? Hardly. If players from the future have an easier time hitting foes from the past, it won't make them any less immune to things like the Black Plague, or a lynch mob, or a burning at the stake. These rules just try to correct the d20 combat system by restoring historical technological inequality.

Sorry if this got long-winded... it's 3am here and I've been awake far too long.

As for you, Buddha- more comes when I think it up. I'm trying to come up with some different causality models, ranging from a simple percentile roll to see if you accidentally prevented your own birth, to the effects of splitting a timeline or merging a timeline and becoming a person torn between both.

 

[Roudi]

Imagine a PC looking for bullets for his pistol in a high PL plamsa gun world. No chance to buy them over the counter and he would have to get them hand made. So the price would be very high.

This is actually a very good point. You'll have to ask why the designers of d20 Future came up with that rule, not me; it is from the d20 Future Sourcebook and can be found in the MSRD.

edit: Found this in the MSRD.

–2 to Purchase DC for each Progress Level lower than the current Progress Level, except in the case of valuable antiques.

Since most gear won't qualify as "valuable antiques" in the far-flung future (though that depends on the setting), I think one can assume that lower-PL gear will cost less in the future. Don't forget, just because it's the Fusion Age doesn't mean that the world sudden stops manufacturing Information Age gear. I think the reduced costs for lower PL gear in higher PL settings demonstrates how more advanced societies can better mass-produce and cheaply build relatively lower-tech goods.

 

[Committed Hero]

I think you should ignore PL altogether. It adds needless complexity to a game that needs none.

 

[Andur]

Well here's the problem of the proposed system as I see it: Armour is made in order to defeat the current weapons and vice-versa. So an armour which is designed to deflect laser fire will not be quite as effective against projectile fire (basically the ideal defense against a laser is a mirror). Personally I like Armour as DR or a derivative thereof much better than the whole adding to your defense thing, the more restrictive your movement and agility is the harder it is for you to be hit?

For future armours I see there being basically one general type that would not do much against anything, than more specialist types, one for energy, one for ballistic, etc.

 

[Roudi]

I agree with your sentiments, Andur - I'd rather see armor as DR rather than a bonus to Defense. Don't forget, though, that the Defense value is an abstract value representing not only one's ability to avoid attacks, but also to shrug off attacks that DO hit you. An unsuccessful attack roll made against an armored character does not necessarily mean that the defender got out of the way; it could mean that the attack hit the defender's armor and was deflected or absorbed (it could also mean that the attacker is a piss-poor shot).

That said, I'll work up some gadgets to allow an easy to-DR conversion of armor, and allow one to construct armor better defended against certain types of attacks.

 

[Masada]

I think time travel should work like Terminator... The PC's arrive nekid. Then you would have to focus your game mechanics on the skills a PC needed to have to use a flint lock, fly starship, read an ancient scroll, etc.

Solves monetary issues too... "I bring all the paintings in Monet's basement with me..."

You'd have to get in to some serious head bending about time paradox as well. What impact would the PC's have if they "help" Madam Curie create an atomic explosion in Paris?

Paradox aside, it sounds fun!

 

[Roudi]

The idea will be to present many different types of time travel, so GMs could model their games around Orson Welles, or The Terminator, or Back to the Future, or The Butterfly Effect, etc. I want to cover the range of options, from the campy B-movie style to the hard sci-fi methods.

As for time paradoxes, I think that could be a chapter unto itself.