Dealing with "Inventors"

[Venatius]

Most D&D games, and many games of other systems, are set in some sort of previous world. Maybe something as (relatively) recent as a Rennaissance type era, or more typically the middle ages. Possibly something a bit earlier, with a Roman Empire, Greek, Babylonian, even prehistoric feel is possible. But a lot of players in my experience, be it out of pure or impure motivation, want to be the ones to move history forward. I'm talking about players whose characters want to invent something.
This in of itself isn't all that horrid at first, not at all. If you're in some primitive-ish society, a character inventing the ballista might be the only way to turn the tide of a war that no combined party action could on its own affect. Unfortunately, the power of a good idea is also its greatest peril. Where does it stop? For instance, a character decides to be the inventor of gunpowder. For one thing, is it really fair to be able to use contemporary understanding and knowledge and retroactively apply it to the character? It's not clear-cut. Many characters in games are startlingly brilliant. In D&D, it's entirely possible to start the game right off the bat with a rough ballpark IQ of 180 (using the game FAQ rule of 10 IQ per Int). Such a character has a level of brilliance that would grant them incredible levels of insight, logic, etc. Then it's entirely possible to take relevant craft skills to back things up. As brilliant as many real-world scientists have been, to use D&D as the template again, it's hard to make the case for many real life people being more than maybe level 3 NPC classes. A 12th level Int 20 prodigy should theoretically be an intellect beyond most known to our history.

The problem is twofold. For one, how DO you really know what ideas such a character, however brilliant, really would or wouldn't come up with? Furthermore, how do you neccessarily rationalize such ideas? Obviously, technologies lead into each other. But the "trees" of technological advancements required can be nearly impossible to trace. The invention of firearms required knowledge of metallurgy, of certain woodworking techniques, ballistics, a little bit of physics, chemistry, etc. etc. etc. The character obviously can't go and invent the musket when no one has even found a reliable way to handle metalworking or gunpowder. I don't think anyone wants to have to accumulate enough info for a twenty page research paper just to settle this topic. Then, of course, what's to stop the player from declaring, "I can't invent the steam engine yet? Okay, so MY guy will figure out coking fuel then!"
Then of course, there's the storyline impact and possible power imbalance of such discoveries. The guy who invents gunpowder suddenly has a frightening material to weaponize, one he can dole out to anyone he pleases, and with no real objective way to determine how much he can produce without, again, going into undue levels of research. Particularly in a primitive and/or low magic setting, someone who can blow open walls, vault doors, dragons, etc. without so much as sacrificing a first level spell slot has gained a frightening asset. Yet they never really had to work for it. All it took was just declaring their character works on inventing it, and likely, just having to wait until you finally bit the bullet and told them they've had enough time to come up with it.

So, how DO you handle reconciling a character's discoveries with the complicated and probably not perfectly understood (by you or the other players, or perhaps by anyone but history professors and/or scientists) web of scientific advances and prerequisites? How DO you balance the story impact and power of an invention of tremendous potential that really requires no actual effort on the player's part? And how DO you deal with saying no to something that there is every reason they COULD come up with, but would simply be a grotesquely unfair advantage? And can that be done fairly without outright stifling creative(-ish) thinking on the player's part? I leave it to you. The problem has come up for me often enough that I badly need some answers, and personally, I have few or none.

I've seriously contemplated trying to come up with some kind of "system" for inventing new thingamajigs, but that would inevitably fail to cover some possibilities unless I just ruled, maybe a bit unreasonably, that ONLY things governed by the system can be invented. And also, the headache of that seems like a bit much.

[Khanderas]

Our world does not have "magic" included in the natural physics.
The game world might not have normal chemical reactions, or what is normal to us. Charcoal + sulphur + salpeter = gunpowder to us, in the DnD world there might not BE salpeter anywhere. Or if there is, it just dont work that way, or is so rare it is hideouly expensive.
Gunpowder might simply not explode, just burn (like in the Zorro movies when they spread it on the ground to make a fuse).

Infact, when looking at steampunk settings, I assume that combustion is not possible (you may have gasoline, it may burn, but just plain dont work that way if you try to build gasoline powered car. Gasoline is for starting fires only here :) ).
They could make a train if they wish, but it would be hideously inefficient and not lead to higher tier tech (such as combustion engine), or not work at all.

Explosives. Dynamite is Nitroglycerin + stabilizer (sawdust or something like that, not important anyway). Nitro is not something you just "mix up". Before Alfred Nobel invented dynamite, Nitroglycerin was used to blow mineshafts. Shake it and you die. Burn it and you die. Not something I would bring to a dungeoncrawl (knocked prone or fireballed ? roll d20. lower then 5 and you do are a stain on the walls.


If the players complain it works in the real world, just tell them this isn't the real world. Harsh, perhaps, I'm just saying game physics don't have to work like Real World -metagame physics.



Edit nr <whatever>: As for inventing things, yes they can do that. But to invent something they gotta explain why they need something. Where would the character get the idea that packing a mix of powders that burns sparkly (and little else when out in the open), in a small pipe with a bullet in the end would propel said bullet with the force enough to pierce metal ? That is assuming that it WILL pierce metal in that world. If not it is just an arrow that costs 100-1000 times more to make (and has to be kept dry to function at all).

Just becuase it is gunpowder, dont assume it is kalchnikov grade results. Derringers were about as dangerous as a slingshot. And a slingshot takes much less time to reload (also see bows).

[Roderick_BR]

Basically, a character can't make up new invents without support from the local available technology. For example, mixing up a dust that explodes when you apply fire, or a real hard impact is easy. Find out how to actually use it in a useful way is not. He'll be, at first, able to create cannons, like the ones used in ships, but to refine it into handguns would take decades to develop, and probably many more people to work on it.

You can just say that a character doesn't have enough support from the currently technology. For instance, where the character will even get the idea of passing steam through pipes to move wheels to begin with? What he'll do with a liquid that explodes when applied sparks? He can make up small inventions, but can't create the whole thing. It takes years of study, and a lot of people to think about several things, and how to apply it on day-to-day life, or even military use.

It's like trying to build computers, but you don't even have the technology needed to build the *tools* to *start* building the most *basic* components. No character can build up the whole thing alone.

[Emperor Tippy]

The real problem comes with players who want to combine magic and tech in perfectly logical ways. Or apply magic to the world at large.

Take the Decanter of Endless Water and a Water Wheel. Thats unlimited energy.
Or a Windmill and some permanent gust's of wind.

Look at permanent teleportation circles. The players can corner the world shipping market in a week or so. And with that control comes lots and lots of power. As in the players can rule the world easily.


Depending on the actual starting tech level of the world and how much of real world physics are known/in play you can do some very nasty things.

"Why yes, that is a kinetic kill vehicle with an impact energy of 20 megatons."

But what happens if that kinetic impacter goes boom inside a closed forcecage? You have 20 megatons of energy contained inside a 10 cubic foot area with no way out.

[Emperor Tippy]

Basically, a character can't make up new invents without support from the local available technology. For example, mixing up a dust that explodes when you apply fire, or a real hard impact is easy. Find out how to actually use it in a useful way is not. He'll be, at first, able to create cannons, like the ones used in ships, but to refine it into handguns would take decades to develop, and probably many more people to work on it.

Actually not really. If you can come up with an explosive compound the uses for it are fairly obvious. The problem is the trial and error involved. You don't get to make mistakes when messing with explosives.

You can just say that a character doesn't have enough support from the currently technology. For instance, where the character will even get the idea of passing steam through pipes to move wheels to begin with? What he'll do with a liquid that explodes when applied sparks? He can make up small inventions, but can't create the whole thing. It takes years of study, and a lot of people to think about several things, and how to apply it on day-to-day life, or even military use.

The steam engine was around pre fall of the roman empire. And as for where the character gets the idea, shear dumb luck. Its where most new ideas/fields come from. The party wizard is making tea 1 day and starts wondering why the top part pops up when the water is ready. He starts experimenting and realizes that steam in a confined area is powerful.

Eventually the wizard decides to make a steam engine. A Decanter of Endless Water, a permanent wall of fire, and 1 adamantium box later and you have a steam engine.

It's like trying to build computers, but you don't even have the technology needed to build the *tools* to *start* building the most *basic* components. No character can build up the whole thing alone.

You fail to take into account things like fabricate. So long as the character can come up with the idea of a computer and has the skills to make it then 1 spell later and he has the computer.

[Funkyodor]

Or you could have the inventor repeat many modern day inventor mistakes and:
Fail to have repeatable experiments.
- Yay you invented a Ballista! Twang! Here comes shot number 2! Snap... What do you mean that was the only shot! Argh!

Unstable experiments.
- Yay you invented the steam engine, and it's going strong, steady outpour of steam, turning and all that jazz. (hooks it up to something expensive and important) Wait the steam output is getting slow... The table is shaking some... Boom! Bit's of metal all over the place.

Lack of monetary flow due to the above.
- Can't make an omlette with out breaking eggs. Unless they are impossible to scramble, then I guess they can't be beat!

Elbow Grease.
- Inventing takes alot of time, effort, and (as mentioned above) money.

Theft of ideas
- It sucks when you put alot into an invention and fail, only for some strange commoner to glance over and through random chance realize where you are screwing up. Whip up the invention by himself and take all the credit. Wow, I guess thats why they came up with patents and the Patent Office.

Lack of foresight
- Wow, what do you call that? The 'Paper Clip'? Sounds stupid! I'll take it off your hands for $5. No? How bout $10? (Hand shake, transfer of funds, and the grinning BBEG departs with his shiny revolutionary device).

[Kol Korran]

I usually refrain from answering questions that try to correlate things/ objects/ science rules between the real world, and any game system. (because it can't- the game world is a game world, and is based on entirely other basic assumptions- mainly, that it should be fun and playable. while the real world doesn't give ahoot whether you like living or not. and we barely even begun to understand how it works anyway), but what you're describing is actually a game problem. so, i'll try to give yousome ideas of how to handle it-

first of all, lets deal with this basic assumption:

Most D&D games, and many games of other systems, are set in some sort of previous world. Maybe something as (relatively) recent as a Rennaissance type era, or more typically the middle ages. Possibly something a bit earlier, with a Roman Empire, Greek, Babylonian, even prehistoric feel is possible.

they aren't set at those eras, they draw inspiration from them. the difference may seem minute, but it is not. none of the historical eras ever had dragons or monsters, magic wether devine or orcane, other competing intelligent races, and so on. in most settings (even those "technologically advanced") the majority of "technology" is still directed towards magical implications (which tend to surpass the "mundane ones by far". teleportation? flight? fireballs? raise dead?). you can tell the character that s/he has grown up in this kind ofworld/ setting, and thus is geared up more towards magical inovations. (i'll get more into "changing disciplnies a bit later). thus- he may create new magic spells and such, but not mechanical thingies. but this may not satisfy you, so-

And how DO you deal with saying no to something that there is every reason they COULD come up with, but would simply be a grotesquely unfair advantage? And can that be done fairly without outright stifling creative(-ish) thinking on the player's part

there isn't every reason for him/hher to "come up with it. (but i'll explain that later). as to saying him/ her "no"... the DnD system is quite broken, and many DMs need to exclude/ alter certain material/ actions/ rules. this is done for game balance and keeping things fun for everyone. that is a perfectly good reason to say "no!". and as to the player claiming it is "creative thinking"... when a player decides to play a renegade dark elf who wields two scimitar do youcall that creative, or copycat? stealing from scientific history i just as he steals from literature. if the player claims "creativity", let him/her invent something NEW... otherwise, s/he is just trying to create an unjust advantage, on the guise of "creative insight".
As simple as it sounds- "just say NO" is my best advice.

but, if you're still worried about "scientific advances", here are a few things you should know about magical reearch through the ages (i'm a bit learned on the subject from my real life background):
- science and research DO NOT advance by some sort of a technological tree. real science and innovation are far more a matter of chance, persistence, observation and ispiration than they are looking at past achievements and saying "oh, we have mettalurgy, it's time to work on steam". science is NOT a civilization game! very, very, very few people were ever able to forsee what the future might hold (the astounding majority of them were artisticaly inclined by the way). it is nearly unanimously accepted in the scientific community that if you'd have taken the human race back to it's beginnings, and then have fast forwarded time. it is CERTAIN that you would have an entirely different technological state now. it is theorised that less than 4% of the technologies would be similar. (and just to make things clear- a car and any other combustion based self propelling automation would be considered identical for this comparison).
my point in this is- just that a certain technology exist, it doesn't mean you can now move to "the next in line" (argumentavly, there are millions "next in line", how do you choose?) so you can argue that to your character.

- science takes TIME. most advances took people years, most time decades to create. true, some of this took money gethering, and preparing the right laboratory and experiments (which a PC should have no problems of accomplishing), but nearly everything else took Time, to experiment over and over again. even today, when scientific breakthroughs are at the fastest rate they ever been, most smimpe advances takes a minimum of a year or two.
can your character take time for that?

- science most times also requires other sources of knowledge other than the self- colleagues, other written material, and so on. this isnot an a requistie as such, but most scientific advances were made possible by such "collection of information and ideas". one of the greatest leaps in terms of science (and humanity in large) was the invention of the Print (which is an intriguing story in itself). less than 0.2% of the worlds "scientists" lived before that. (and the birth of the computer marked the beginning of the realy exponential growth of knowledge).
does your character have the needed resources? the colleagues? they might be envious.

- disciplines: nearly all real world scientist dedicated themselves to a specific discipline (the more talented ones could dablle in another), and usually a particular field inside that discipline. Darwin couldn't do squat in engineering. Einstein knew nothing "construcive" of Biology. Leonardo dabbled in many things, but finished nearly none of his works! (and most of his inventions, contrary to poular belief, never would have worked.).
in order to gain that high knowledge in your discipline, it usually demanded expertise in many smaller fields. many breakthroughs were due to the extensive specialization, and accumulation of specific knowledge, by one (or a few) person/s.
the point in this- can the character says is specialized? it has dedicated her life to the adventuring life style. suddenly she is an inventor? you could check the desired invention, and then declare that "you need knowledge 10 in mechanics, knowledge 10 in ballistics, proffesion 12 in siege engineer, craft 8 in ...." and so on. this will either dissuade the player, or at least creae some "cost/ benefit mechanism".

- the "breakthrough barrier" (there is a far more accurate term, and explenation ofthis, but i've chosen the simplistic version): even if your theory is right, the experimental conditions at a peak, and still it didn't succeed. you see mto be doing everything jsut right (including things you've done before and worked!) and still you don't get the result. this oculd be to some minute detail you missed, or, more probably- something you are completly unaware of and have no way of explaining or measuring. NEARLY ALL of scientifically "assured data", still has some unexplainable phenomnons about them (even fire- we still don't know WHAT it is exactly, or why does it makes those patters... strangely enough, most of the most basic concepts in the scientific world are far from fully understood, explained, or defined- life, energy, order, chaos, rule, number, matter, and more...). in most new discoveries there are weird unexplainable phenomenons. later, someone explains part of it, but raiseseven mroe questions.
the point is, you could let you player try to build something new. but he will have to roll some roll to make it actually work, and it still might have bugs later.

enough ranting about science i nthe real world. if that didn't help you, a few short advicesfor your game:
- again, "just say no". the player is not "creative", s/he is just abusing the rules to change the ballance of the game. s/he wants to be creative- let him find a way to achieve his/her goal within the confines of the rules and the world as it is.
- alternetavly. declare that the basic knowledge. proffesion and craft skills represent skills in the normal state of the world (theoretical approved knowledge, ability to craft every known world object of that field, and so on). the "inventing spark"- the ability to go beyond normal understanding demands more- double (or triple) the skill points. (i.e.- knowledge 12 in war machines allows you to understand all the influences mechanisms of the lizardman's rock thrower, and the common crossbow. knowledge 12 (inventor- costing double or triple the points) in siege engines might give you the insight to combine them to create the ballista)
- demand the players invest the time and other hindrances that take to (perhaps), make a breakthrough, as i detailed above.
- if you do allow inventions, is till suggest you make some sort of test/ roll to see if it worked, and if it has bugs. the roll can be lowered/ bugs reduced if the invention is less ambitious/world power changing.

still, if it realy throws your game of bend- just say no

[holywhippet]

In the fictional world used in the book Magician by Raymond E. Feist, he has a simple way of dealing with gunpowder - it just doesn't work. You can mix up charcoal, saltpeter and sulfur to your hearts content, it just will never go boom (technically only gunpowder ignited in a confined area explodes) when you try to burn it. The Gods have decided not to allow it and they have the first, last and only word in the matter.

As for technology not advancing - basically it's the path of least resistance. If you can do something difficult with magic, then you do it with magic. Since magic can do it, nobody feels the need to invent some other way of doing it.

Back to gunpowder though, Feist writes his books in the world that was invented by his old RPG group when they played in University. Occasionally other creatures find their way onto this world via rifts. One such group was a platoon of Scottish musketmen. During the players adventure, they got their hands on the musketmen's weapons and were annihiliating all that stood in their path with such powerful weapons. The muskets were only working because the nearby rift was allowing reality from their home dimension to leak in and let them work. Unfortunately for the players, when they moved too far away from the rift they found themselves surrounded by enemies and the muskets stopped working.

As for the problem of players trying to invent things. I'd require them to have lots of ranks in knowledge: engineering (and possibly alchemy). I'd also require them to make a roll on a d100 with a very slim chance of success - this would simulate the odds of actually coming up with a new idea. As well as that, perhaps a intelligence check would be a good idea. Finally, I'd require them to have a prerequisite need for the invention like working in a field that would benefit from the invention for quite some time.

Or, you could just tell the player no, they can't do it.

[Titanium Dragon]

I think one thing worth noting about the whole "IQ" thing is that, really, they AREN'T all that smart. An IQ of 180 may SOUND very high, but is it really?

The answer is "not really, relatively speaking". IQ is a metric used to compare to the average, but the average intelligence of people has risen sharply since midieval times; in the 20th century, the Flynn effect has caused IQs in first world countries to increase by approximately 3 points per decade.

To put it into perspective, the average IQ of people in sub-saharan Africa, according to some studies, is like 50-60. In the US, you'd probably be mentally retarded with an IQ that low; there, it is average. Why? Because an education and good nourishment make you smarter. This may seem bizzare, but it has been bourne out by numerous studies; I'd say taking that average IQ and applying it to midieval Europe would not at all be unfair, given they, too, were a largely uneducated and malnourished lot.

Someone with an IQ of 180 is really smart, but if you say 100 back then was 60 today, you're looking at someone with an IQ more like 140 today. Even someone with 23 intelligence would have an IQ score today of only about 170, which is really high, but not beyond reason. I have an IQ in that range and trust me, while I'm smart I don't exactly advance the world's technology by a hundred years. Indeed, it seems I mostly spend my time typing stupid posts on forums. Hm... Anyway! >>

Your intelligence is relative to what is known, and no matter how smart you are you just can't really do things you have no ability to make useful predictions about. The Greeks, for instance, figured out that the earth was round, the distance to the moon (highly accurately), the distance from the Earth to the Sun (not accurately at all), and some of them even figured out that the Earth orbited the sun, not vice-versa (something which it took a very long time for people to accept).

Sure, Leonardo Da Vinci was a rediculous genius - he came up with designs for tanks, flying machines, and parachutes, but apart from the parachutes, a lot of his "futuristic" technologies simply weren't implementable. His aircraft, for instance, could fly, but it required materials far stronger and lighter than were available in midieval europe. And even being a rediculous genius, most of his ideas weren't implemented.

In the history of mankind there have been a few great engineers who have come up with things in advance of their time, but just a high intelligence doesn't really make up for it - it is more than sheer intelligence which leads to these things.

So, what does this all mean?

1) High intelligence should not be used as an excuse to advance technology hundreds of years; no one in the history of mankind has pushed the forefront of knowledge more than a decade or two ahead. A few Greek philosophers, Da Vinci, Galeleo, Newton, Einstein (well, really, a lot of early 20th century scientists), Bacon, and a handful of others have pushed the forefront of what was possible, but even they didn't push it all THAT far ahead.
2) High intelligence is not even as high as it seems to indicate; an IQ of 180 back then is not the equivalent of an IQ of 180 today.
3) Saying "real world people are not high level" is silly; in D&D, to have the ranks in knowledges I have, I'd have to have rediculous numbers of HP and the like - the average PhD has at least a +15 bonus to their primary skill check, for instance. Clearly, D&D does not model this aspect of reality well; Einstein, Da Vinci, and similar people would have been practically epic, if not actually so.

I think those are reasonable rules of thumb; basically, you're limited to the technology of the time plus twenty years if you're an absolute blindingly driven genius. If you aren't, then it is unlikely you'll even do that much; there are tons of smart people who don't push the forefront, and most likely, the smartest people who ever lived did not really accomplish much of note.

Chemistry was not at all understood back then; it took a very long time before the elements were discovered, and while achemy, a protoscience, did exist, it was quite primitive.

Fundamentally, if someone wants to be a dork and invent gunpowder, then make them figure out how to make the stuff from raw materials. If the player is too lazy, then the character clearly isn't driven enough to care. Of course, this somewhat breaks down if you have someone like me at your table, but hopefully people with a great knowledge of chemistry and an interest in the history thereof aren't going to try and get their character to invent things the DM probably doesn't know how they work or understand the full consequences of.

It would require a lot of effort on the part of the player to look up such things to your satisfaction, and you just say no to anything too rediculous.

It is also worth noting that guns and gunpowder weren't actually all that good - it has been noted that Longbows were probably far more effective weapons up until the 18th century, and possibly later than that; what really drove the adoption of the gun was its ease of use. Its a complete pain to train someone in the use of a longbow, but teaching someone how to use a gun is much easier, even if the gun is an inferior weapon. Heck, if you use the rules in the DMG for guns, they're terrible - why would someone bother inventing them? They suck, and that's probably fairly reaslistic for primitive firearms.

People have this mental image of gunpowder really changing the world, but ultimately, gunpowder really isn't all that special. The chinese invented it long before the europeans - centuries, even. And yet, somehow, the Chinese didn't take over the entire world the way the Europeans did, and even lost to invaders well after the invention of gunpowder.

You fail to take into account things like fabricate. So long as the character can come up with the idea of a computer and has the skills to make it then 1 spell later and he has the computer.

Beyond the fact that you lack the craft skill to make a computer, a computer would be a crafting check of about DC 1000. And that's probably being generous. You simply couldn't make a computer with a crafting check, because you lack the tools to make it. Even magic doesn't do things so fine. And, honestly, I don't think a human can even hold the image of a microelectronics board in their head; I know what one looks like and how it works, but assembling a trillion transistors would take an absurdly long period of time by hand, and even magic is not going to fix that.

As a rule of thumb, I'd apply the following:

1) Require them to take the "Inventor" feat. This allows them to use knowledge/crafting/profession skills to create new knowledge, as appropriate.
2) They need to do the research on this themselves and convince you, OOC, that it is possible using the tools of this time period to do whatever.
3) This takes 1 week of work for each 1 gp value of the final product.
4) Each week of progress costs 100 gp.
5) At the end of your work, you make a DC 50 check. If you succeed, you have invented what you are trying to invent. This check may be modified by magical items as normal, but if you want a temporary magical bonus to apply to the skill check, you need for that magical bonus to have applied for all of the time spent working on the invention. If you fail, all the gold and time you spent was wasted and you cannot try again until you gain another level. You may not take 10 on this check.

If you were feeling generous you could lower the DC to 40 (which is defined by the PHB as "nearly impossible") but I chose 50 as I consider it beyond that difficulty. Not to mention...

1) Skill bonuses are rediculous. You can get an item which gives you +10 to your skill modifier for 10,000 gp. This, already, puts it to 40.
2) Ability bonuses can be quite high. At level 10, its not unreasonable to expect a +7 ability modifier off a character trying to pull this. 33.
3) At 10th level, they've invested 13 ranks into that skill. Now its down to 20, which is rollable.
4) Skill focus brings it down to 17.

And that's ignoring all the other random stuff which can be stuck in in various ways; synergy bonuses, racial bonuses, and feats which give +2 rather than +3. If a character devoted themselves to doing this, it is not unreasonable for them to be able to succeed, but if you feel people are likely to abuse it, do something like this to make it more difficult while seemingly reasonable.

Basically, figure out at what point you want to make this reasonable; if you wanted a character devoted to it to be able to succeed at 10th level, you'd want something like DC 50. If you wanted it to be more epicish, you'd need to raise the DC by at least 10; I know swimming up a waterfall is DC 80. Feel free to say no if you consider it more difficult than that. Or you could just assign such arbitrarily high numbers.

After all, Leonardo Da Vinci didn't spend HIS bonus feats on Exotic Weapon Proficiency. :P

[Roderick_BR]

You fail to take into account things like fabricate. So long as the character can come up with the idea of a computer and has the skills to make it then 1 spell later and he has the computer.

But doesn't the character need knowledge of what he's doing for fabricate to work at all? I don't think someone can just cast fabricate and make up a working computer with it's own power suply and everything.
A curious example? There was a Hawk & Dove story where they go to some other world. Getting there, they find out the natives use a "magical metal" that can be shapped by thoughts. They use it for adaptable weapons, armors, and vehicles. When Hawk gets a hold of some, first he makes a uzi by mentally detailing all the parts of a uzi, and then he starts making helicopters and short distance radios. He had the knowledge for it, but the natives, despite having said metal for mileniuns, never thought about using it for complex machines, let alone fire arms and flying machines. Even if they had the idea, they wouldn't know HOW to make it work. A metal bird that flaps metal wings? A crossbow that shots metal pieces at nearly the speed of sound? They don't have the know-how for it, despite having sages with lots of intelect(Int) and knowledge(Wis) gathered for ages (books, tools, and skills taught to others).
Similarly, one could use the Tech Levels from GURPS. The further the Tech Level between the character's knowledge, and the wanted device, the harder it is to operate or create. It was something like this: Medieval (pre-steam engines) was level 3, and post-steam engines was 4. Moderm computers are something like 6 or 7. You get a -4 or something on related skills, if the device doesn't already exists and is common knowledge. If your wizard want to create a steam engine, he just takes a -4. To make a car, he would take somewhere between -12 and -16. Only a high level character would came up with such concept, but the again, high level characters are almost gods.
I'm not saying it's impossible, but it would be harder to make a gas-powered engine than a steam-powered one for a medieval character, because he lacks tools (that need to be invented and created), and all the small details.

So, yeah, you can be awfully smart, use magic (or magic tools), and have enough knowledge, but without a basis for your hypothesis, you won't go far. Even if you do start, that start will mostly be used as a basis for others. Developing a whole new type of device can take a lifetime.
Another example: In Megaman Battle Network 5, there's a VR video thing that shows a group of scientists wraping up their findings, saying that all their breakthroughs would be better used by future generations with access to better technology. They just admited that they hit a cap that they wouldn't be able to bypass so easily, and probably would spend the rest of their researchs trying to improve on their tech, not working directly on their main projects. They knew they couldn't advance more, so they were preparing things for the new generations to come. That's an interesting view, even for a game where their scientists could create virtual reality places, and real artifical inteligence.

Good points on the rest, though I'd point that accidental research could be considered "acts of god".

[FLAvatar]

I highly recommend the Guardians of the Flame series by Joel Rosenberg which - in addition to being a heck of a fun read - deals with exactly these kind of problems.

In short, a college gaming group gets transported into their campaign world by magic. One of these players is an engineer and another, by virtue of never being able to settle on a major, has a very eclectic breadth of knowledge on everything from animal husbandry and farming innovations to city planning. Real world physics worked just fine, and the engineer got to invent flush toilets and showers and concrete and steam engines and gunpowder while the dilletante accelerated the rest of the world through a few centuries of innovation.

The story managed to keep suspension of disbelief due to the most real constraint of all - time. It only took the engineer a year to find good enough sources of sulfur and saltpeter to make his first batch of gunpowder, but it was several years until he produced a workable gun. Other disciplines had to advance to make things possible, for instance he got lucky and found a few dwarves that were competent enough metallurgists to make a gun barrel that was strong enough not to explode. Development was also slowed, because they realized they had to keep their techniques secret. Their arch-enemies weren't happy at all about the good guys having guns, so our heroes faced raids, theft, extortion, blackmail, assassination, sabotage, and ... well I've spoiled the book enough, but hopefully you get the picture.

The world was about average on the prevalence-of-magic scale, which had to help too. If magic is everywhere, invention takes a back seat - no matter how good your lightbulb is, it ain't Continual Light.

[Capt'n Ironbrow]

In WFRP ed 1 (wich I play), the "Academic Class" has several careers of renaissance/medieval scientists who can "invent" something, there's also the advanced career of the Scholar.
For inventing, we test on Intelligence and add a bonus for the Skill "engineering". Constructing features Dex and engineering again, but basically, it's actually only dedicated Engineers who decide to invent something entirely new. There are several more skills that can help your character build or create like: Carpentry, Smithing, Metalurgy, Mining (can be used in Architecture) and boatbuilding.

Basically our group allows inventions, especially from people who have a career as engineer. The current Dwarf Engineer of our group is quite a passionate inventor, but is so good to keep things practical and relevant. Most of his work is just improving on known designs and "pimping" chariots, warships and the like. His one original invention thus far is the "Zwinkel-Stick", which is a pole on which you can attach different tools and blades. The tools/blades are attached by a screw mechanism. This invention required the use of Smithing and Metallurgy for the proto-type. If I recall, he uses it as a 2-handed axe at the moment but can turn it into a mallet, pick axe, rake or spear in half a minute (screw loose, get new tool/blade, screw on). It does help that of the 3 guys in our group whose characters have the skill, one is a student industrial design and the other a constructionworker who has a passion for carpenting, so we usually keep things realistic and don't go to extreme Da Vinci-like genius.

Inventors in RPG's can be difficult though, especially when they want to make irrelevant things just for their (role-played) intellectual fulfillment. However, when will they get time to do that in their lives of quests and adventures?

In my opinion, as long as the invention is practical and relevant and the inventor has the abilities to draft a design and make a proto-type it's a nice (short) assignment for the character during the session. If characters lack any technical or craftsmanship skills, it would be difficult for them to come up with usefull inventions their players come up with. Involve a test for both the chance the characters can actually think of it... also, these inventions could be very unstable due to a lack of technical skill...

Cool! how delightfully relevant, go ahead inventions:
- Utility tools
- Relevant improvements on existing things (pimping a chariot before a race, a better mechanism for artillery like stone throwers in war)
- Some animal-inspired mechanism (jaws, claws and wings... requires skills related to anatomy too.)

Let me think about it inventions:
- Totally revolutionary devices unlike anything other in the "known world"
- Nice idea, but irrelevant to the situation (i.e. you don't need to do that right now and don't have the time to)

[Burley]

I'm playing a character now who is all about inventing stuff (working up to Effigy Master). I'm in the midst of creating the first bicycle, or at least working on the designs. I know it isn't as revolutionary as steam power and all that, but it's the first.
However, after declaring that my character is doing so, it dawned on me that there are no paved roads, and I must therefore also invent shocks, and shifting gears.
If your player wants to invent something, force them to do it step by step. Taking two things that exist and putting them together is one thing, but creating something all on it's own is something else, entirely.
Also, many players think they're being really clever when they want to make things like gun powder or walkie-talkies (heard D&D planning of how much it'd cost and stuff), but they're really just wasting a lot of time trying to create something that can be done for half the cost by a wizard. (Grenades can be made with 6th level spell, and two devices that allow communication between each other if you're within 200 yards of each other, without wind and no thick walls between you...hell, walkie-talkies usually suck so bad, I'd sell them for the cost of a Feather Token...)
Inventing does take time. If your players have any sort of quest/adventure, they wouldn't have time to stop and study and work for months and years. If there is downtime, you have the right to cause the next great evil to arise a few months before they finish their work, forcing the player to either postpone his gamebreaking activity, or roll up a new character and forget about the old one anyways.

[Blanks]

Its like drugs - Just say no ;)

The way i handle this is
1)
Tell the players that they are ruining the game. If they really want to play with guns, why are you playing a fantasy game in the middle ages?

2)
If someone persists, or tries to "spring it on you" like suddenly combining the elements of gunpowder, there is a simple solution as have been mentioned by others:
It just doesn't work.
Gunpowder won't burn, you can't summon antimatter, steam doesn't move stuff and so on.



I would also argue against "giving them a chance but making probablities small". It works wonder untill someone actually succeds that one in a million roll. Suddenly your players have gunpowder and they rightly feel they have earned it so you can't just take it away.

just my 2 cents.



EDIT:
just thought i would add:
My group usually also limit ourselves regarding "modern feel" magic effects. The idea that spawned this rule was:
Crossbow with a small cylinder and a continual light inside - perhaps even with a red prism at the end. Easy to make and very cheap, but it breaks the versimilitude.

[Timmit]

Gunpowder might simply not explode, just burn (like in the Zorro movies when they spread it on the ground to make a fuse).

Gunpowder DOES behave like that in our world...

[JBento]

Indeed. Only when in a tightly-enclosed space do you have, shall we say, a bang for your buck

[Solo]

Its like drugs - Just say no ;)

The way i handle this is
1)
Tell the players that they are ruining the game. If they really want to play with guns, why are you playing a fantasy game in the middle ages?

2)
If someone persists, or tries to "spring it on you" like suddenly combining the elements of gunpowder, there is a simple solution as have been mentioned by others:
It just doesn't work.
Gunpowder won't burn, you can't summon antimatter, steam doesn't move stuff and so on.

Having steam not be able to move things creates many logical problems. Shall i list a few for you, or can you figure it out for yourself?

if you eliminate too many physicl laws things become rediculous.

"What's that you say? I can't use magical lighting to improve crop yields? Do plants not use photosynthesis? Hey, that means I can grow plants in the dark!"

"What you say? Cells don't exist? ATP doesn't function? That must mean people don't need to eath to get energy! Hey guys, don't waste your money buying rations, you'll be fine." (Note: supported by RAW. You don't die if you fail to eat for months, though you will go comatose eventually. But you never die)

"What you say? Steam doesn't move stuff? But that means that heat doesn't cause air to expand. Hey, that means wind shouldn't exist!"

Which would lead to

"Hey, there must be some device for making wind! We should set up wind mills around it and get free power!"

[Burley]

Solo's Above Comment

I think you're implying that all D&D campaigns are set on Earth. It is a scientific fact that Physics are based on our planet's standards. Steam doesn't work the same way at different altitudes, either. Air Pressure has to be within certain parameters to make steam solid enough to move something, but gaseous enough to rise. It's perfectly within a DMs right to say, "Sorry, but gravity is just a little different here, as is the air pressure." Heck, there is not rule that says that D&D characters survive off of Oxygen. From what I've read, you have Air and you have Water. If you can make fireballs out of guano and sulfer, you can make breathable air out of the same, for all I care.

Photosynthesis doesn't work off of light, it works of off radiation given by the Sun. Plants grow in sunlight, and the only spell I've ever seen that acts as sunlight is Daylight. If you want to constatly have bright sunlight on your crops, you'll just have to watch them whither from the heat. (If you want your plants to grow, use Plant Growth...)

Building a windmill with endless wind would be just as usefull as forgetting about the entire windmill, and having a set of Mage Hands pedal the bike from Gilligan's Island. The Windmill can turn corn into meal, but the Bike can power the radio!

[Kyace]

Beyond the fact that you lack the craft skill to make a computer, a computer would be a crafting check of about DC 1000. And that's probably being generous. You simply couldn't make a computer with a crafting check, because you lack the tools to make it. Even magic doesn't do things so fine. And, honestly, I don't think a human can even hold the image of a microelectronics board in their head; I know what one looks like and how it works, but assembling a trillion transistors would take an absurdly long period of time by hand, and even magic is not going to fix that.

*sigh* Computer does not equal Integrated Circuit.

[valadil]

I haven't dealt with this particular type of player too often in game. Usually inventor players will come up to me during other games and start babbling about what their gnome invented this week, once again reminding me why I don't game with that type of player.

Inventions are much easier to come up with in hindsight. Yes, we all know how a channeled explosion from gunpowder can launch projectiles. Yes we even know what gunpowder is made of. But do you really think your character will just happen upon it when there are so many other materials available to work with?

Magic shunts technology. When a spell like fireball is so readily available, who needs dynamite? The thing about technology is that it stems from other technology. You need gunpowder before guns. But if already available magic is so prevalent, gunpowder won't turn any heads. It's weaker than a fireball so who is going to bother investing time in it?

On a more philosophical note, technology beyond one's grasp often is referred to as magic. If somebody brought a small pistol into the Forgotten Realms, that pistol would be considered magic by the locals. It may as well be magic because it functions based on powers they do not comprehend. We accept that a mage casting fireball understands what goes into casting the spell, just as a marine understands how his flamethrow works. What this boils down to is that if a player really wants to invent something, let him do it in a way that mimics magic very closely. A pistol could be magic missile. A flamethrower is fireball. It doesn't alter the game that much in the grand scheme of things. An inventor could be played as a wizard with very different flavor. (Alternatively an actual wizard who believes he's an inventor and is always coming up for mechanical explanations for the spells he casts could be fun too.)

[Roderick_BR]

The story managed to keep suspension of disbelief due to the most real constraint of all - time. It only took the engineer a year to find good enough sources of sulfur and saltpeter to make his first batch of gunpowder, but it was several years until he produced a workable gun. Other disciplines had to advance to make things possible, for instance he got lucky and found a few dwarves that were competent enough metallurgists to make a gun barrel that was strong enough not to explode.

I guess this explains better what I meant by a inventor not being able to create things by himself. The rest of the technology available for him needs to support creation of new things.
If you are in a prehistoric setting, you can't start building armors and swords if metalurgy itself was not created yet, for example.

[vanyell]

usually when I deal with inventions etc. that may break my game world, I just substitute the desired energy, for magical energy.

example.

"you mix the sulfur, charcoal and salpeter in an enclosed area, compress it, and add a spark to it. suddenly nearby, lanterns are snuffed out all around you, and you feel a gust of wind. you open your chamber, and find the gunpowder gone"

mixes a lot of problems, though, you need to come up with some kind of table to get enough random magical actions. (rod of wonder works, I guess)

[Yakk]

Mythic reality is a simple to involve D&D.

Why is there wind? Because spirits of the air cause it.

Why does the water flow? Because water spirits cause it. Rapids are where there is an angry water spirit.

Earthquakes -- earth spirits.

Why do plants need the sun? Because the sun-spirit (or sun-god) makes the plants grow. Your artificial light is light, but unless it has the power of the sun-god, the plants won't grow.

On the other hand, if you can get an Earth-god on your side, you can have an entire ecosystem growing in darkness.

At the level that D&D is played at, you don't need all of the laws of physics of today for the world to work. Neither do you have to follow the rules of the game exactly as written (ie, the instant-gnome-message-network).

Naive physics can work as it does in our world without having the same underlying deep physics and chemistry and biology that our world does.

[Frosty]

So, what does this all mean?

3) Saying "real world people are not high level" is silly; in D&D, to have the ranks in knowledges I have, I'd have to have rediculous numbers of HP and the like - the average PhD has at least a +15 bonus to their primary skill check, for instance. Clearly, D&D does not model this aspect of reality well; Einstein, Da Vinci, and similar people would have been practically epic, if not actually so.

Einstein can have a +15 bonus to Physics by level 5. Possibly less if he started out Venerable.

8 ranks + 4 Int bonus + Skill Focus (Physics) = +15 to Physics.

[Rutee]

The real problem comes with players who want to combine magic and tech in perfectly logical ways. Or apply magic to the world at large.

Take the Decanter of Endless Water and a Water Wheel. Thats unlimited energy.
Or a Windmill and some permanent gust's of wind.

I like how Arcanum: Of Magick and Steamworks Obscura handled that. Magic utterly suspends the laws of physics. Setting a magickal sword down next to a fulcrum and lever will cause the lever to behave in ways that it's not supposed to. Science and Magick just don't work together.

And no, I don't need to know the specifics on why a Magus is going to cause a train to explode if they ride it. It's sufficient for me as GM to know they /do/, so I can make up the reason /why/ myself in some way that's appropriate.

[Azerian Kelimon]

Rutee, I sentence you to cause Epic Wins in threads you visit. Anyone who has played and enjoyed Arcanum is Epic Winsauce.

Though Disintegrate still wins anything, even supposedly immunes. Guess it's the Pun-Pun of Arcanum.

[Tengu]

What about playing Arcanum and finding it a very mediocre game with a huge, but lost potential?

[Azerian Kelimon]

What about the humour, the spectacular subversion of the Chosen One, being based on the goddanged Fallout, and having clocks acting as indicators of magic?

Oh, and the followers. Right up there with BGII's, methinks.

[Tengu]

Very tedious and imbalanced gameplay, and a horrible gap between magic users and everyone else didn't allow me to experience what you just mentioned - maybe it changes much later in the game as the furthest I ever reached was late Tarant, but the NPCs I met so far were pretty generic and there wasn't a lot of humour.

This game is worse in every aspect (apart from the setting) than Fallout despite being released later and by mostly the same people.

[Rutee]

I considered Technology to be more powerful, but Technologists to be weaker. The most optimal route in general is to have a balance between Magic and Tech, while loading out magick as much as possible. High Technology was fun, but unnecessary; Almost anything you could want made with Tech, you will find for free.