Monitors: some like it hot 1

So I want to have another look at heat mechanics. They seem like an important part of the mechanics, and they're also something I don't know of a parallel to in any game I've seen (admittedly that leaves plenty of room) because they're effectively a curve with a peak of efficiency and Bad Things at either end. I like the idea of a points mechanic, because it feels intuitively nice to be gaining heat tokens as you warm up, and then spending them as you head off into the cold. However, I'm also not sure that a fundamentally additive and threshold-free mechanic is going to be a good match for our curve. I'd also like something that's relatively simple to use in play, because while I want it to be a core mechanic, it's not really something you need to do anything that fiddly with. I want something significant, but slick.

A point worth bearing in mind: whatever mechanic I want to use should also be not completely incompatible with the use of non-reptiles elsewhere in the game. Just something to think about.

Basically this will be another one of my thinking-out-loud posts, so it's a bit messy and long-winded and entirely devoid of silly artwork. Bonus points if you guess the outcomes earlier than I did.

Issues in temperature mechanisms

There are several main issues to consider in terms of the temperature mechanism for Monitors.

• Body temperature, which determines activity levels
• Environmental temperature, which either supplies or absorbs heat
• Insulation, which reduces transfer between body and environment and so maintains body temperature
• Specific heat/light sources, which allow a reptile to warm up regardless of environmental temperature
• The slowing effects of low temperature, which means losing heat is a problem
• The heat-shock effects of high temperature, which means absorbing too much heat is a problem
• Inevitability – heat loss or gain is a physical law, not a personal or dramatic choice, and failure to at least loosely follow the science will make the system ridiculous

Possible pitfalls

In a straight token pool system, a Monitor might choose to take damage from cold, rather than spend heat points to avoid it, allowing them to keep acting at full capability in arctic conditions. This would lead to a ridiculous situation where they are simultaneously taking damage from being cold, and warm enough to run around at normal speed.

In a points-per-turn system based on environmental temperature, problems would arise when Monitors use insulation to maintain a body temperature different from the environment. You could say that insulation modifies the points, but then simply donning insulating gear would effectively warm you up, whereas inability to warm up without a heat source is one of the key features of heterothermy.

The main issue is though, in a genuine heat points system, what would heat points actually do?

• You could use heat points to determine actions, where you receive points per turn based on body temperature. At this point, though, it’s just another name for action points, and you’re tracking body temperature on a chart.
• You could have a large pool of heat points, and allow limited spending to perform extra actions or gain a bonus on skills. Points would be lost when in cold environments. Broadly speaking, this gives greater competence at higher temperatures.

General principles

• At average body temperature, you can perform perfectly well.
• At low temperatures, you become slower and clumsier, and find it increasingly difficult to do anything well. Your metabolism slows, reducing healing, digestion and the effects of drugs, illness and poisons.
• At very low temperatures, you slow to a crawl and eventually to a standstill.
• At high temperatures, your metabolism can perform more efficiently, allowing you to move faster, react more quickly and heal better. However, chemicals and diseases will also take effect more quickly.
• At very high temperatures, your body is no longer able to adapt to the heat. You overheat like any other creature, becoming exhausted, and eventually suffering pain and injury from the heat.
• Direct application of extreme heat or cold will damage a reptile as it would anything else – the temperature difference is simply too large for them to cope, so they will be frozen or burned accordingly.
• In environments hotter than you, you tend to get hotter.
• In environments colder than you, you tend to get colder.
• It takes time to warm up or cool down and adjust activity accordingly.

Experimental models

Ten-point tracker

This model simply uses "points" as a tracking system on a scale that determines activity levels. As I mentioned before, you'd gradually change body temperature to suit the environment, and insulation would help you to resist this change.

Heat points	Description	Actions	Skills/Speed	Notes
0	Torpid	-	-	Metabolism stops
1	Very cold	Minor only	-2	Metabolism slowed
2	Cold	Major only	-1	Metabolism slowed
3	Cool	Major + Minor
4	Average	Major + Minor
5	Average	Major + Minor
6	Warm	Major + 2 Minor	+1	Metabolism increased
7	Warm	Major + 2 Minor	+1	Metabolism increased
8	Hot	Major + Minor
9	Very hot	Major + Minor	-1
10	Overheated	Major only	-2
++	Heat Shocked	-	-	Unconscious

Notes on Tracker

Naturally, the exact effects of temperatures would depend on other mechanics for the game; I wouldn't necessarily be using Major + Minor actions, for example.

This system seems to cover all the principles I outlined above. It calls for checking your activity against the chart to determine activity, which is potentially a burden on the player; I've streamlined it down from my original idea but I suppose it could potentially be simplified even more. The chart could be cut down to five states, say; on the other hand it could be expanded to weight sections differently, which would generally mean giving players a bigger safe zone. This would depend on likely rates of heat loss and gain in play. I'm inclined to say that slightly larger pools are better because it makes the loss or gain of one point less dramatic, and this makes it easier to judge and take risks, provide challenges that penalise without crippling characters, and so on; Dan's analysis of this problem in Deathwatch pretty much covers it.

There might be some confusion because it's not completely symmetrical.

Large Spendable Pool

In this system, heat points are actually spent. The heat points pool is very large, perhaps even 100 points, and we assume that tactical considerations and spending limits will avoid major breaches of physical law.

Any environment has a temperature rating. Monitors will gravitate towards it, losing or gaining heat depending on their body temperature and insulation. This might range from 10 per minute when stark naked, to 3 in thick woollens, to a percentage chance of losing even 1 point when wearing a genuine spacesuit.

Heat points can be spent on a small number of specific things, probably only once per turn:

• bonus on skill rolls
• faster healing
• additional actions

So, let’s say you’re moving into a Temp 20 set of tunnels (cold) from your nice warm Temp 50 vehicle. The Captain is wearing combat fatigues, lightly insulated, and will lose 5 points per minute as she gravitates towards ambient temperature, which will take a mere six minutes; on the other hand, she’s mobile and can react quickly for now. The Engineer, on the other hand, has a bulky insulated suit that reduces heat loss to 2 points per minute, which means she can act more or less normally for half an hour even in these tunnels, but is impeded by her bulky suit. When a clutch of skitterbugs burst out of a side-passage, both characters can start spending heat points every round to make additional actions or take more effective shots. However, the Captain’s player needs to watch this spending, as a few rounds of high-spending combat will leave her slow and vulnerable until she can find a new heat source. In contrast, the Engineer’s player can spend fairly freely.

Once in the tunnels, the pair... actually, they can continue to spend points even when very cold, because they'll actually gravitate back up to the higher temperature. Nope, this model is not going to work! But let's continue.

Emerging (slowly) from the tunnels an hour later, our pair find themselves in a huge greenhouse (Temp 70). The Captain warms up to normal function in only four minutes (and to toasty warm background in ten), while the Engineer will take ten minutes to reach normal capability, and a whopping twenty-five minutes before she's as warm and active as the Captain - and will still have the bulky suit impeding her. However, with a constant supply of heat coming in, the two can spend heat points without a care in the world.

In this system, the player balance is between spending heat points early on while you still have them, and keeping a supply of heat for long-term use.

You'd have to find a balance between the cost of bonus actions, the size of the pool, and the speed of temperature change.

Problems:

• It would difficult to make this work in both short and long term consistently. A very large pool with slow point loss would allow players to act with impunity for long periods unless actively chilled by something. A small pool would make long-term activity in cold environments very difficult. Working a suitable balance out would be very difficult.
• The present system doesn’t really model the effects of low temperatures, nor high temperatures. Both should cause general impairment. High temperatures have a particular problem, because it's actually in the player's interest to spend heat points to minimise any damage caused by excess, but that makes them more effective with heat rather than less. I could tweak the system by requiring a heat point spend for every action, but this would need very careful balancing to allow more than a few minutes’ activity. What about using insulation as a modifier on that spend, and having the per-turn heat spend include an action? However, all this would ultimately do is add a lower bound, not model impairment; and that can be done anyway simply by stopping activity once you run out of heat points.
• In this system, simply being in a warm environment allows you immediately start spending points like water. It doesn't even have to be warm - just warmer than your current body temperature! There's no mechanical sense of taking time to gradually get warm again, and being stiff and awkward for a while after you come in from the cold.
• Similarly, being in a cold environment makes it unwise to spend points, even if you're very warm and highly insulated, because you can't regain them. This feels wrong to me. A warm lizard in a spacesuit should stay highly active and effective in the cold of space.
• If you have a low cost to bonus actions, then you can take these even at low temperatures. However, if you have a high cost, then in a cold environment you'll cool down immediately unless insulation also reduces the cost of actions.
• Insulation is powerful, and needs careful balancing against other considerations, such as speed, armour and clumsiness, especially if different players are likely to take different levels of insulation.
• If you can drop below the background temperature, then insulation is a burden as long as it reduces heat change to less than the cost of an action.
• If you can't, then you can take bonus actions forever as long as they cost less than the current temperature rating.
• I tried some messing around with insulation that cuts the cost of actions, and a few other things, but nothing works. Fundamentally, unless any change in heat points is affected by body temperature and environmental temperature and insulation, it's not going to work. That's getting pretty complicated already.
• What about things like drug metabolism? This should be faster at higher temperatures and slower at low temperatures. You can’t make players spend points on things like that (particularly for poisons etc.) and you’d need to set boundaries for when a GM can do it so they know how to avoid unfairness – don’t want the GM spending all your precious heat points on poisoning you!

On this initial pass, it seems to me that:

• points pools are very good for modelling dwindling supplies, but don't handle over-saturation well.
• spendable pools are good for choice-based mechanics, but not so good for cause and effect.
• a point-adjusting model is likely to make the environment-body interaction fiddly because constant adjustment is called for.
• most importantly, a replenishing points system based on relative factors has fundamental patterns of supply and cost that don't model resource limitation well.
• the interaction between environmental temperature, body temperature and insulation is quite complex and difficult to model in a point-spending system.

Tap and Burn Model

An alternative point-pool model would involve tapping and burning of heat points depending on insulation levels.

1. A Monitor would spend heat points every round to do things like move or use skills. These would be tapped.
2. At the end of their turn, they can untap a number of points equal to their insulation value.
3. Any excess tapped points are lost.
4. Warm environments, or basking near heat sources, allow you to gain heat points.
5. Heat gain is also modified by insulation.
6. Any time you would gain heat points but are at maximum, you take damage instead.

In the following examples, Cold is Heat 2, Warm is Heat 10, and Hot is Heat 18. Assume that you can spend 1 point to move, use a skill or gain a bonus on a roll, to a maximum of 5 points per turn. Good insulation is 4, poor insulation is 1. These are all arbitrary.

If somewhere cold:

• Warm reptiles with good insulation can spend points fairly readily, which models the high activity and efficiency appropriate for this situation. However, unless they have perfect insulation, it's tactically best for them to be less active than an equally warm reptile in a warm room.
• Warm reptiles with poor insulation can spend plenty of points, but will rapidly run out. This allows them to act effectively for a short period, then slow down. However, they can also conserve points to avoid losing them, which is problematic; they can trudge slowly in the snow for hours on end, then suddenly have a burst of activity.
• Cold reptiles with good insulation don't have many points to spend, but will recover all of them, so they can consistently act slowly. This could work okay if point supplies and costs are well-balanced, allowing them to do a small number of actions per turn.
• Cold reptiles with poor insulation will rapidly run out of points if they spend them. This makes it sensible to conserve points, which models their torpor at these temperatures. If they have no insulation, it's best to do nothing at all.

If somewhere warm:

• Warm reptiles with good insulation can spend points readily, which models the high activity appropriate for this situation. Depending on the way heat gain works, they could potentially gain heat, which is a problem.
• Cold reptiles with good insulation don't have many points to spend, but will recover most of them and so keep acting slowly. They can potentially gain additional heat points over time. Their best option is to remove layers and try to warm up faster.
• Cold reptiles with poor insulation will lose any points they spend, but will gain heat points easily, so they have a way to replace them. However, if heat points are only gained slowly (one a round, say), it's possible for them to burn their full supply each round, keeping them effectively slow and awkward because their pool will not increase. Alternatively, they might build up a sizeable pool, but then lose it all in a few rounds of activity, despite being somewhere warm.
• Warm reptiles with poor insulation: depending on the way heat gain works, they could potentially gain heat, which is a problem. If the rate of heat acquisition is low, they can easily run out of points despite the temperature, effectively cooling down!

If somewhere hot:

• Warm reptiles with good insulation can spend points readily, which models the high activity appropriate for this situation. They would slowly gain heat, which would allow them to do more until they overheat.
• Warm reptiles with poor insulation can spend points, because even though they burn them, they'll gain fresh points. They will rapidly overheat and take damage, and ideally ought to either seek shelter or wrap up.
• The best mechanical option for everyone is actually to spend points as quickly as possible, making them effectively fast and effective rather than impeded by the heat. If the rate of heat gain is slow, then this problem is reduced.

Notes on Tap and Burn

This seems to work as expected for insulated characters, but fall down badly without insulation.

Reptiles can simply avoid spending points in cold situations, which is fine when they're cold, but problematic when they're hot. You can stand quite happily naked in a freezer without losing points, as written, as long as you don't do anything. You can hoard points for long periods by not doing much, then spend them when it's convenient.

There is a kind of fluffy long-term effect of background temperature, but it isn't actually enforced in the short term. Warm reptiles can act slowly and clumsily in the cold to retain points for later; colder reptiles can spend all their points to do one thing very effectively; and getting hot makes you more likely to be active and efficient, not less.

This system would need very careful balancing between multiple factors: the rate of heat acquisition, the effects of insulation on heat loss and gain, the size of the pool, and the cost of activities. I am wary of anything that needs pinpoint balancing.

Overall, I can't really see this system working. It seems to me that dealing with the problems would involve adding several points of complexity, and having players do arithmetic every round to determine exactly how many points they start and end with. Moreover, some problems seem to call for a low rate of heat gain, while others call for a high rate.

Thermal Hit Points

Let's briefly consider a model where heat points work rather like conventional hit points, and are lost through cold or regained through heat-based "healing".

1. Reptiles have a capacity of 10 heat points.
2. Environments are classified with brutal simplicity as "Cold", "Moderate" and "Hot", with only "Moderate" being survivable in the long term.
3. A Cold environment, or exposure to cold, damages your heat points.
4. A Hot environment, or exposure to reasonable heat, heals your heat points.
5. Insulation gives a (non-optional) die roll to soak changes to heat points.
6. If you run out of heat, you go torpid.
7. Any time you'd exceed your capacity, you take damage instead.

The first disadvantage here is that players are naturally going to be inclined to max out heat points unless they expect to face Hot environments, as there is no phasing-in of impairment. The second is that there's no penalty for being cold until you actually go torpid, so you can act completely normally.

On the plus side, this would probably work okay for non-reptiles, because you just either give them very small heat capacities or none at all, and have them simply take damage whenever their insulation fails.

The solution to both disadvantages seems to be adding thresholds for impairment. Let's say, outside the 3-8 range the difficulty of everything goes up one step: I've already mentioned using broad scales of Difficulty (which gives modifiers) and Speed, so using these keeps things within an existing system where you don't need to track exact modifiers, just the number of them. This way, you'd slow down and be less effective outside core temperatures.

This doesn't cover changes to general metabolism, which is a shame, as I think that has interesting dramatic and tactical possibilities.

You know, what we've ended up with is a tracker. It's just an even simpler version of the first one, isn't it?

Closing remarks

Of the models I tried here (and a couple that didn't even make it this far), both points models seem pretty much hopeless. It might just about be possible to salvage some version of the Large Pool with very careful parameters; I'll take another look when I'm awake again. However, it really does end up being a very complex model, with interaction between (at least) maximum pool, current pool, background temperature, disparity between temperature bands, minimum temperature, maximum temperature, value of heat-point bonuses, and insulation. More or less all at the same time.

Some version of the tracker seems usable to me, despite not being a points system, and I have to admit I'm finding it the most appealing model so far because it actually seems a lot less fiddly, which is unexpected.

I have also had an idea for an alternate (and somewhat complicated) tap model, which I'll discuss next time, unless it looks too boring to talk about.