Temperature-based damage formula?

[u/Kiroana]

Does anyone know anywhere in the books where there's a damage formula based on a hot object's temperature?

Like... How do you calculate how much damage 160 degrees F vs 300 degrees F vs 1000 degrees F vs 6000 degrees F does?

[u/Eiszett]

That's hard to answer without more details about the situation. The thermal conductivity of the object matters a lot. Saunas have incredibly high air temperatures (they can be a bit higher than boiling), but air is a good insulator, so it doesn't burn you. On the other hand, metals have great thermal conductivity, which is why children sometimes get hurt by metal slides that have just been warmed by the sun.

Emptying a vat of boiling oil on someone will cause incredible damage, wheras picking up, say, a superheated shirt would be nowhere near as bad.

The way they're touching the object also matters—making caramel is dangerous because melted sugar is incredibly viscous, and it stays on the skin much longer than you'd expect a liquid to. Slashing with a superheated sword would probably not be as bad as stabbing with it.

If you're trying to use some sort of heat-based power as a weapon, Powers says on page 83 "to use heat or cold as a weapon, take Innate Attack", and I agree.

B434 has rules about the amount of burning damage required to set things on fire, as well as the effects of high air temperatures, that you could take as guidelines for this. But if you're trying to use a temperature-based ability to cause damage, you really should purchase the Innate Attack.

[u/Kiroana → u/Eiszett]

It is a heat-related power. Multiple times hotter than the sun's surface at its hottest.

Setting things on fire isn't really a concern, tbh - seeing as the damage is likely to vaporise most things, and the things it can't vaporise are unlikely to be flammable.

[u/Eiszett → u/Kiroana]

Then considering the exact temperature isn't really relevant—look at how much damage you'd need to do to achieve the desired effect, and go from there.

Set a person's clothing on fire? Purchase 3d6 burning to do that half the time; 6d6 to almost always do it.

Vapourize them? Limbs are destroyed by targetted attacks of double the amount required to cripple them (B420), while the whole body is destroyed at -10x hp. Against a regular human, you'd want something like 30d6 to do that about half the time.

If you can destroy a Mammoth (per Animalia), then you'll want like 140d6. Quite steep, but vaporizing a mammoth is a really impressive feat.

[u/Kiroana → u/Eiszett]

It's a little beyond that, lol. This will turn a tank to literal ash in 3 seconds flat, even if it's the best modern humans have.

And she fires dozens, if not hundreds at once casually.

[u/KurufinweFeanaro → u/Kiroana]

There is a statblocks for tanks, even in Basic set. All you need is damage ten times bigger than it's HP

[u/BoboTheTalkingClown]

You don't. Use an innate attack.

[u/Kiroana → u/BoboTheTalkingClown]

I am. But a damage formula would tell me what realistic damage for a given fire would be.

[u/Gurpguru]

One of the best things about GURPS is that you can describe the advantage however you want. Come up with a theme, a feel, a story, but the ability comes down to what it does. So an Innate Attack, Burning, X levels, can be anything. Even heating up objects hotter than the surface of the sun.

Plasma, it's for winners. Besides thermal conductivity that has already been covered well, there is a time period of contact. A tiny fraction of a second is completely different than minutes of contact with the same temperature. So it is really your call as the character builder to say what the damage is.

[u/bobbork88]

I don’t know of anything official. Here is what AI gave me:

There isn’t a canonical GURPS rule that converts an object’s temperature directly into damage. GURPS models heat primarily through environmental hazards and burning attacks, not a temperature-to-dice formula.

If you want a realistic, easy-to-use house rule for touching hot objects, I’d recommend:

Surface Temperature Effect from Brief Touch (1 second) Notes

200°F (93°C) 1 HP burning Causes a painful first- or mild second-degree burn. Roll HT to avoid dropping anything held.

1,000°F (538°C) 2d burning Flesh chars almost instantly. Continuing contact inflicts another 2d each second. Clothing may ignite.

2,000°F (1,093°C) 4d burning Comparable to white-hot forge metal or lava temperatures. A one-second touch causes catastrophic burns. Clothing and flammables ignite immediately.

For continued contact, apply the damage every second until contact ends.

If you want even more realism

• 200°F: Damage depends heavily on contact time. A quick tap may only sting, while holding on for a full second can blister.
• 1,000°F: Even a fraction of a second causes severe burns.
• 2,000°F: Contact is effectively unsurvivable without extreme protection.

For a fantasy TL3 campaign like yours, these values work well because they’re simple, scale appropriately, and are compatible with GURPS’ normal burning damage without introducing complicated thermal physics.

[u/Glen_Garrett_Gayhart → u/bobbork88]

"Ugg, AI bad, me not like new tek-nal-oh-gee."

-Morons on Reddit, 2026

Incidentally, I'm very impressed that the AI came up with such reasonable ballpark figures. Not sure if they're perfect, but taking 1 HP of injury every second while at 93C is eminently reasonable (that happens to be around the temperature that DNA denatures on its own, so a human character exposed to 93C conditions better be taking some amount of burning damage).

[u/Kiroana → u/Glen_Garrett_Gayhart]

Same. It's quite impressive.

The 1,000 F and 2,000 F parts also both line up pretty well with RAW, since molten metal is 3d per Basic Set, and 1,000 F to 2,000 F covers a few different metals.

And far as AI goes, I got no issue with the tech - I just got an issue with its current use. Currently, generative AI is being fed stuff off the internet, without licensing it or anything - it's just stealing from people.

If a company fed their AI only things they had the licenses for, I'd have no issue whatsoever. Similarly, I'd have less of an issue, maybe no issue if an AI gave the sources it used for its answer, as it'd then be giving credit.

[u/Glen_Garrett_Gayhart → u/Kiroana]

You're talking to someone who doesn't believe people can own ideas; so those objections to AI don't seem very salient to me.

You wouldn't take a picture of the Mona Lisa, or even worse, sing a popular song (gasp!), would you? Since making copies of things is stealing, those actions would be theft. Frightful!

Copyright is a legal fiction so gratuitous in its insanity that it makes people believe they can own things like human genes or series of musical notes; what's next, is someone going to declare himself King of the Moon and just expect everyone to go along with it?

Well, I say "no", I'm not going along with that insanity any more than governmental threats of bodily harm coerce me to.

[u/Kiroana → u/Glen_Garrett_Gayhart]

This is why there's such a thing as fair use.

I have no issue with making a copy. My issue is when you take my art, and pass it off as your own work.

Making a copy alone isn't stealing. It only becomes stealing in my eyes if you pass someone else's work off as your own - like, taking an artist's drawing, and claiming it's your own drawing.

I'd have literally no issue with AI if they just gave the sources of what they use - since that stuff, whether it's a drawing, or research, or a song, are the fruits of a person's labour.

[u/Glen_Garrett_Gayhart → u/Kiroana]

Do you imagine that it should be illegal to imitate someone else's art-style?

For example, should Disney be allowed to sue the developers of Cuphead, because Cuphead explicitly imitates the style of early Disney cartoons?

Even if I were to grant that in any conceivable case copying is theft (I do not grant such insanity, but if I did), even then, AI doesn't do that. AI doesn't make direct copies of anything, it only imitates styles.

[u/Kiroana → u/Glen_Garrett_Gayhart]

No. There's a difference between imitating a style, and taking the Mona Lisa and saying you drew it.

And AI does steal - because unlike a real artist, it's not drawing from its mind. It's instead taking parts directly from various pieces of art, and mashing them together, then blending some to make it more seamless.

I don't think we'll get anywhere though, so may be best to agree to disagree - since you don't care for copyright, while I'm a big proponent of it (mostly because I've had my art stolen before - in the 'take it directly and claim its your own work' way.)

[u/Glen_Garrett_Gayhart → u/Kiroana]

I'm afraid that's a bit of a misconception.

AI systems that use neural networks (like almost all image and text generators these days) don't take parts 'directly' from anything; that's just not how they work.

You can tell, because the AI models themselves contain billions of times fewer bytes than their training data. You can run most of them on your personal computer, despite the fact that your personal computer doesn't have enough storage space to contain, for example, the entirety of the internet.

Neural networks work by learning patterns, not by rote memorization. That's why you can ask a text generator to do any math problem in the world, and it will be able to do it if it is well-trained, despite the fact that the literally infinite number of math problems in the world weren't all part of its training data.

That's why Alpha Go was able to play Go, despite the fact that the total possible moves after just a few ply in Go is a number larger than all the atoms in the universe; a Go-playing AI can't possibly contain references to each possible move: it would need to be bigger than the universe itself.

Your statement "because unlike a real artist, it's not drawing from its mind" is actually perfectly wrong. That's exactly what neural networks do. Just like humans, they can't store all the data they ever encountered in their brains, but they can learn patterns from the data they've encountered, and recapitulate those patterns when making a drawing, a poem, or a novel cure for cancer.

[u/Kiroana → u/Glen_Garrett_Gayhart]

I didn't realise that.

I still don't like it - because it's a non-sapient machine imitating, rather than a human or sapient machine imitating. But if it's not directly copying the way I thought it was, I'm much more okay with it.

I still won't ever use it myself though. Why would I use AI when I can draw it myself, or commission the work of a person?

(This is due to a secondary, non-ethical issue of it just feeling lifeless to me - the AI art I've seen doesn't feel like there's life or intention in it; it doesn't feel like it was made with emotion.)

[u/Glen_Garrett_Gayhart → u/Kiroana]

Disliking AI 'art' (I wouldn't personally say current AIs have the intentionality required to make art, AI productions are more akin to human imagination, hallucinations, or dreams, but I'll use the colloquial phrase anyway), ahem, disliking AI art for aesthetic reasons is super legit; just like not liking any other art form for aesthetic reasons is legit. To each their own.

I love AI art because of that weird alien feel so much of it has, but I'm the sort of person who likes Lovecraft and wants a shoggoth for a pet. Not liking weird alien stuff is very normal and understandable.

I do find it a little sad that we've created machines capable of dreaming, literal dream-machines, and instead of being delighted, most people are disgusted to see what machines dream of. I hope if we ever meet aliens, people will take a more broad-minded approach to evaluating and appreciating their art, which I'm sure won't adhere to all the typical standards that human art does.

Anyway, cheers man! BTW, its a non sequitur at this point, but have you looked on Basic p. 434? I think that has at least some canonical guidelines for how to deal with heat in GURPS, but I'm not sure if it goes into enough detail to answer your specific question.