Burning fields

[ntg84]

If a square section of a field catches on fire wont the entire field eventualy burn? Im talking about a grain field in the summer when its growing tall. Its pretty dry and would burn pretty quickly. So why does only a small section of a field burn?

[OberGrupenStompinFeuhrer!]

Because of the hamsters.

[Guest Michael emrys]

Hey, OGSF! Hadn't seen you around for a while. You been gone, or do I need new glasses?

Michael

[Guest Madmatt]

Having fires spread is not currently implemented but is on the 'List' for future inclusion.

Flame retardent Hamsters ARE included though free of charge...

Madmatt

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[This message has been edited by Madmatt (edited 08-31-2000).]

[Lorak]

Not to mention my CCT's... we love to roll in the ash baby.

Lorak

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Proud commander of the CCT's Chinchilla Commando Teams

[Guest Michael emrys]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Madmatt:

Flame retardent Hamsters ARE included though free of charge...<HR></BLOCKQUOTE>

...Who parachute from airplanes ahead of the flamefront and wet down the tree line. Brave fellows, those.

Michael

[Von Brizee]

I wonder if the newbies who ask questions wonder what the hell is wrong with us and our Hamster obsession?

[Ash]

Hmm, volkshamstergrupenfirefightennwettindowntreelinehampestergruppefuhrercomenstalin

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The names Ash, Housewares

[This message has been edited by Ash (edited 09-01-2000).]

[OberGrupenStompinFeuhrer!]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Michael emrys:

Hey, OGSF! Hadn't seen you around for a while. You been gone, or do I need new glasses?

Michael<HR></BLOCKQUOTE>

I've been here and there...not posting too much though, gotta be careful these days with so much controversey about! Liable to get one's ears boxed.

I did post to a thread entitled "we've seen those flags" and unveiled the much vaunted KruppSpringenHamsterFlingenMachinen.

However, I still keep clear of the SS-Hamstertruppen-soggy-bummed-piddle-pants when buying units.

OGSF

[Ash]

My hamsters run in their wheels so much they think they're overrunning poland.

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The names Ash, Housewares

[This message has been edited by Ash (edited 09-01-2000).]

[Bullethead]

<BLOCKQUOTE>quote:</font><HR>If a square section of a field catches on fire wont the entire field eventualy burn?<HR></BLOCKQUOTE>

Gawd, and I just spent all last night fighting a hay fire....

But to answer your question, in general the answer is MAYBE . Depends on conditions and especially on the wind. That is, if the wind is going N-S, the field probably won't burn much E-W.

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-Bullethead

Want a naval sim? Check out Raider Operations at www.historicalgames.bizland.com/index.html

[Bullethead]

Madmatt said:

<BLOCKQUOTE>quote:</font><HR>Having fires spread is not currently implemented but is on the 'List' for future inclusion.<HR></BLOCKQUOTE>

You know, in this case, it might be a good idea to re-examine the tactical effects of burning fields before BTS puts too much work into this feature. My position is that the game should distinguish between different types of outdoor fires because they have different effects. My main point is that I don't think most burning grass and crop tiles should totally block movement or LOS. This is because of how such fires work. I base my opinions on my experiences as a rural firefighter.

When a field of grass or crops burns, the fire spreads outward from the point of ignition in an expanding ring. This ring is very thin compared to the total area of the field--it's exact width depends on many things, especially the size of the burning plants--so the result is that only a tiny fraction of the whole field is burning at once. Both inside and outside the ring, there is no fire to speak of. Hence, there is no reason why units shouldn't be able to exist in the vast bulk of the tile's area.

The question, therefore, is whether units can cross through the ring of fire to make use of the rest of the tile's area. There are 2 main cases here: short plants (grass, young grain, and post-harvest stubble), and tall plants (ripe grain).

For short plants, the flames seldom get above knee level in height and the width of the fire ring seldom exceeds 1 foot. Nor is the fire of uniform size around the ring; there are usually long segments of relatively large (max size shown above) and small (match-sized) fire around the perimeter. Thus, vehicles and troops have no problem crossing the ring of fire almost anywhere they choose--I do it all the time w/out needing special clothing. Any detours required to avoid the bigger patches of fire would be smaller, I think, than the scale handled by CM in 20m tiles, so could largely be ignored. Thus, burning tiles of short plants should not impose much, if any, movement penalty.

Taller plants like ripe grain, however, are a different matter. While the fire forms a ring just like that discussed above, the flames are much bigger and more intense. Thus, it is hard or even impossible to cross through the ring of fire. So while the vast majority of the tile might be free of fire, getting to it would be a problem. Thus, having burning tiles of tall plants be total movement blocks IMHO would be OK.

That's the movement effects, now for LOS effects. In general, the bigger the fire in the field, the more it and its smoke block LOS, but all burning fields seem to be pretty smokey anyway. So IMHO, burning short plants shouldn't totally block the LOS, but should impose a pretty serious degradation, while burning tall plants should be a total LOS block.

So in summary, IMHO fires in grass and short crop tiles shouldn't impose much if any movement penalty, but should create a decent smokescreen effect. Tall crops, OTOH, should block both movement and LOS, at least for the duration of the fire. I believe CM could handle these distinction because IIRC it already tracks the height of grain fields for seasonal LOS effects.

Now on to the spread of fire in pastures and grain fields. It seems to me that the taller the plants, the faster the fire spreads by itself. Thus, fields of short plants burn slowly but ripe grain takes off. Adding wind greatly increases the speed of spread downwind but slows it significanly upwind and to the sides. Spread downwind is aided by flying sparks starting new fires outside the main ring.

Thus, IMHO on calm days, short plant fires shouldn't have much chance of spreading, but tall plants should. Add wind and both types should have a very good chance of spreading downwind, especially tall plants, but not much chance of spreading in other directions.

One more thing about the spread of grass and crop fires. "Spreading" isn't really a good word for the process, because it implies that more and more tiles become totally engulfed. But what really happens is that the ring of fire advances over the ground. IOW, you have unburned plants, then a thin strip of fire, then an expanse of ashes. So if the game determines that the fire has entered a new tile, the original fire tile should no longer be burning because the fire front has moved on.

The foregoing concerns only fires in grass and crop tiles. Brush and tree fires are different and should, IMHO, continue to burn and block movement and LOS for the duration of a CM battle, regardless of spread to adjacent tiles.

DISCLAIMER: All the above are merely musings to help a game approximate reality. Nothing herein should be construed as definitive statements as to real life fire behavior and safety. All fires are dangerous--stay away from them.

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-Bullethead

Want a naval sim? Check out Raider Operations at www.historicalgames.bizland.com/index.html

[Daveman]

Geez, sounds like they'll have to add FireAI to the game just to handle all that.

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"You know our standing orders. Out of ammo become a bunker, out of commission become a pillbox, out of time... become heroes." - The Beast

[Bullethead]

Daveman said:

<BLOCKQUOTE>quote:</font><HR>Geez, sounds like they'll have to add FireAI to the game just to handle all that.<HR></BLOCKQUOTE>

I don't think so. Movement and LOS effects would depend on terrain tile type and time of year just like they do now. As for "spread", BTS is already going to write code for that at some point anyway. On that issue, I was just suggesting that instead of creating a bigger area of burning tiles in grass and grain fields, the burning area should move across the map. That is, the fire starts in tile A, then tile B ignites and tile A goes out.

The main new thing, I think, would be replacing burnt-out tile A by a new tile type, an ash field, just like dead buildings get replaced by rubble. Ash fields should have the same movement effects as grass, provide no cover to troops, and have only a small LOS effect from scattered, lingering hotspots such as smoldering cow pies.

IMHO, field fires advance fast enough to warrant this treatment within CM's scale. Even a light breeze can move the fire front downwind at a rate of like 1 tile per turn, or even faster, depending on the dryness and size of the plants. So in just a few turns, you could convert a large grain field into ash.

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-Bullethead

Want a naval sim? Check out Raider Operations at www.historicalgames.bizland.com/index.html

[L.Tankersley]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Bullethead:

All fires are dangerous--stay away from them.<HR></BLOCKQUOTE>

I guess I'll be eating these pork chops raw, then. I'll tell the kind folks at the emergency room that you told me to stay away from fire.

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Leland J. Tankersley

[Daveman]

Just kidding... I should have added a few choice smileys to my post.

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"You know our standing orders. Out of ammo become a bunker, out of commission become a pillbox, out of time... become heroes." - The Beast

[David Aitken]

Thanks for the info, Bullethead! It would be all too easy to get caught up with the accuracy of armoured vehicles and such, and forget about the accuracy of the battlefield environment. =)

David

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There's a splinter in your eye, and it reads REACT

[Mark IV]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Bullethead:

So in just a few turns, you could convert a large grain field into ash.<HR></BLOCKQUOTE>

You may wish to expound on the spread of building fires, as well. As it is, they are either fine (not burning at all), or completely engulfed in flames. The apparent effect is of instant Hollywood-style mass combustion.

Some distant future, Fire-Smart CM might have the bulding catch fire a section at a time, with corresponding increases in LOS blockage and casualty-producing ability as the fire spreads.

The backblast from a 'zook is a fearsome thing, but will rarely ignite an entire building instantaneously with immediate catastrophic loss of life.

Personally, I could go for a moratorium on new versions, until there are a bunch of major things to roll in at once. There's nothing seriously broken right now, and keeping up with differently-flavored PBEMs has been taxing.

[Bullethead]

Mark IV said:

<BLOCKQUOTE>quote:</font><HR>You may wish to expound on the spread of building fires, as well. As it is, they are either fine (not burning at all), or completely engulfed in flames. The apparent effect is of instant Hollywood-style mass combustion.<HR></BLOCKQUOTE>

I did this a couple months ago in another thread, with the able assistance of our other resident firefighter, Echo. Do a search on the word "flashover". But I'll summarize briefly.

Basically, flashover (defined in that other post) is the point when a small fire in a room (such as a piece of furniture) suddenly causes the entire room and everything in it to burst into flames at once. This happens because the ceiling and walls of the room trap most of the heat of the 1st fire. There are MANY variables affecting how long it takes for a given room to flash, but in general it's not long at all--only a few minutes. And once 1 room goes like this, usually the attic quickly follows (even if several floors above), and then the adjcent rooms cascade along. So in a few minutes more, the entire building can be engulfed and starting to collapse.

Now, understand that the point just before flashover is the absolute limit to what fully equipped firemen can survive, even with their suits and air tanks and hoses. Well before this point is reached, the room and most of the rest of a small building will be uninhabitable for unprotected personnel. This is due to smoke, poison gases, and INTENSE heat. So if you take 5 minutes as an average time for a typical room to flash (a figure often cited but by no means an absolute), then about 1/2 that time or less is a reasonable guess as to when non-firemen have to evacuate.

So, for these reasons, I don't have a problem with the way CM buildings burn. As I see it, various prior hits have started small fires earlier in the game, even the same turn. When the building ignites in CM, then, it's reached the uninhabitable point. Which for CM-sized buildings will usually only be a couple minutes after the 1st small fire starts. Sure, in real life there wouldn't be all the flames just then, but there will be in a few more minutes. The important thing is the game effects, which accurately reflect reality. Troops have to leave, and LOS is blocked by serious smoke.

BTW, Hollywood building fires are total BS. They show unprotected actors running around in plain view between little jets of fire and a few falling, unburned boards. Yeah, right. In real life, you usually can't even see the fire itself very well even from a few feet away, due to all the smoke. Naturally, you can't breathe without an air tank, either. And that smoke is HOT, so you have to have a suit on. So basically, forget everything you've seen in movies about unprotected guys running around in fires.

<BLOCKQUOTE>quote:</font><HR>Some distant future, Fire-Smart CM might have the bulding catch fire a section at a time, with corresponding increases in LOS blockage and casualty-producing ability as the fire spreads.<HR></BLOCKQUOTE>

I'd rather see "CM: Engine Company", where instead of soldiers and tanks you have smoke eaters and big red trucks .

<BLOCKQUOTE>quote:</font><HR>The backblast from a 'zook is a fearsome thing, but will rarely ignite an entire building instantaneously with immediate catastrophic loss of life.<HR></BLOCKQUOTE>

Well, this goes into the fires from prior hits building up thing. I mean, how many times does a schreck hit with the 1st shot? So just assume that the earlier shots started some small fires that have built up to the evacuation point by the time of the last shot.

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-Bullethead

Want a naval sim? Check out Raider Operations at www.historicalgames.bizland.com/index.html