HTML Version 1.3, December 28, 1995

Frequently Asked Questions About the BFG9000

By Tony Fabris

Contributors, in alphabetical order:

Doug Bora ....... Content, Editing, Proofing
Tod Bouris ............ Content, Playtesting
Chris McAllen ......... Content, Playtesting
American McGee .............. Technical Data
Dean Stretton ..................... Proofing


This text is intended to give the public information about some elements of the computer game Doom and its sequels, by id Software. This text was not written by id Software, so bugging them about its contents is probably a very bad idea.

Additionally, the computer game referenced in the text is of an adult and graphic nature. In no way is this text intended to promote violence of any kind. Any references to violence in this text are meant in relation to the playing of the computer game, not real violence. The author is adamantly non-violent.

Additionally, this text is being presented in the form of a computer file. Any illegal or damaging activity related to the use or transfer of this or any other computer file is not the responsibility of the authors.

Trademark Information

All specific names included herein are trademarks and are so acknowledged: id Software, DOOM, DOOM II, THE ULTIMATE DOOM, QUAKE. Any trademarks not mentioned here are still hypothetically acknowledged.

Copyright Notice

This article is Copyright (c) 1995 by Tony Fabris. All rights reserved.

You may make and distribute copies of this work in original form, so long as the copies are exact and complete, the copies include the copyright notice in its entirety, and the copies are in electronic form. You may not charge any sort of a price or fee relating to any copies of this work in any form.

Table of Contents

Section 0 - Introduction Section 1 - BFG Basics Section 2 - The Direct Hit Section 3 - The Blast Area Section 4 - Deathmatch Techniques Section 5 - Submitting Corrections

Section 0 - Introduction

0A. What is this FAQ about?

A FAQ file, stated simply, is a Frequently Asked Questions file.

This FAQ file describes, in as much detail as possible, the behavior of the BFG9000 weapon in the MS-DOS version of the games Doom, Doom II, and The Ultimate Doom. It is not intended to answer general questions about the game itself. Please refer to the other FAQ files for help in other areas of the game. You can also frequent the* newsgroups for more information.

We began writing this FAQ out of necessity. We were frustrated at the apparent inconsistencies in the way the weapon seemed to behave during game play, especially during deathmatches. There were times when we would get killed by the weapon when we thought we were completely safe. Conversely, there were times when we thought we had used the weapon correctly against an opponent, but they walked away unscathed.

Our intent is to provide players with enough information to attack effectively with the BFG, and to correctly defend against it in a deathmatch. Our hope is that this information will give players a new attitude toward the weapon. We want to transform it from "The weapon we love to hate" into "The thinking man's weapon".

0B. How was the information in this FAQ obtained?

The primary source of information was American McGee at id Software. He patiently answered our questions while this FAQ was in its draft stages. He corrected several serious errors in our descriptions of the way the weapon calculates damage. He provided us with a great deal of detailed information, and reviewed the file during its development. His help was invaluable in putting this FAQ together.

Most of the other information here is a result of careful testing during game play. Testing was performed on Pentium computers running the MS-DOS versions of Doom II and The Ultimate Doom. Tests were done both in single player mode and in 4-player deathmatch mode. Testing was performed on the regular levels as well as custom made levels. In some cases, a special .WAD file was created to test situations that would be difficult to reproduce with the regular levels.

0C. How accurate is this information?

Fairly accurate. Accurate enough to base your playing strategies on. However, it has not been tested with every single version of Doom, and there may be differences among platforms. In addition, at the time of this writing, we were unable to verify every single item with American McGee. Quake is the big project at id Software at the moment, and he didn't have a lot of time to devote to us. As a result, some items in this file are strictly conjecture, regardless of how carefully they were tested. Please see section 5 if you suspect this FAQ contains erroneous information.

0D. Where is the latest version of this and other FAQs?

The latest Doom-related FAQ files and other documents can be found at all of the Doom mirror FTP sites. The central location for the Doom mirrors is at However, that site is usually quite busy, and you may need to locate another mirror site from which to download. Listing all the mirror sites is beyond the scope of this document. See the 'DOOM: Rec.Games.Computer.Doom FAQ' or 'DOOM: FTP and WWW Sites' postings in the* newsgroups for a complete list.

The URL of the directory that contains the Doom FAQ files (usually in TXT format, compressed in a ZIP file) is:

The latest official version of the BFG FAQ is also posted monthly to the and .playing newsgroups. This is part of the RGCD Periodic Information Postings (PIPs). If your news server does not keep the articles long enough for you to find one of the PIPs, they are archived at:

The official location for the hypertext version of the BFG FAQ is DoomGate on the World Wide Web. Check it out here, along with some other good documents:

Section 1 - BFG Basics

1A. What is the BFG9000?

The BFG9000 (or BFG) is arguably the most powerful weapon in the computer games Doom, Doom II, and The Ultimate Doom. It is also the most difficult weapon to use well in a deathmatch (multi-player competition), because it does not behave in a simple 'point and shoot' fashion.

When you have it in your arsenal, the BFG is selected by pressing the 7 key on your keyboard.

When you pull the trigger, there is an excruciatingly long pause as the weapon warms up. Then a large green ball of plasma is emitted from its barrel. The plasma ball flies in the direction you fired it until it hits a target or a wall. Like all weapons in Doom, it will fly straight through decorative objects like torches or trees.

When the green ball hits a solid object, it detonates and does two types of damage: Direct Hit and Blast Area. Each damage type is outlined in its own section, later in the FAQ.

1B. What does 'BFG' mean?

The general consensus is that BFG stands for Big Fragging Gun. Well, that's the G-rated version at least. That's from Hank Leukart's "Official" Doom FAQ.

The term 'frag' is used in Doom to represent a confirmed kill in a deathmatch game. This comes from the idea that in a deathmatch, you are killing your fellow space marines. The definition of frag, according to the dictionary, is:

    frag Slang. Verb, transitive
    fragged, fragging, frags
       To wound or kill (a fellow soldier) by throwing
       a grenade or similar explosive at the victim:
       "He got fragged. Blown away" (Bobbie Ann Mason).
Other good name suggestions that have found their way to the authors are "Big Funny Gun" (Chris Somers) and the much more logical "Blast Field Gun" (William D. Whitaker). As of this writing, we have not confirmed any of these with id.

1C. Where can I find the BFG in the game?

Listing all the locations that the BFG can be found is beyond the scope of this document. For detailed information on the location of all weapons, please consult the other FAQ files. Keep in mind that the BFG appears more often in deathmatch games than it does in single-player games.

1D. What is the cheat code for the BFG?

While you are playing the game, type the keys IDKFA to give your marine all weapons, keys, and ammunition. Then press the 7 key to select the BFG.

Note: This cheat code is disabled in multi-player games and single-player nightmare-skill games.

1E. Why is the BFG missing in my version?

If you perform the above cheat correctly, but do not get the BFG, you may be playing the shareware version of Doom. You must purchase the commercial version of Doom from a retailer or id Software before the BFG can glorify your screen.

1F. What's this I hear about the original BFG?

The current version of the BFG is not the way id's designers originally envisioned it. According to a recent thread on the newsgroups, the BFG behaved quite differently in a pre-release beta of Doom. Several people independently reported this feature:

Apparently, it worked by shooting multiple streams of different types of plasma and fireballs. Because this required an unusually large number of moving objects, it tended to slow down the game. Therefore, the BFG was redesigned with the invisible blast area that is used today.

This may explain why the behavior of the blast area is so unusual. It seems that the trace calculations still use some of this old code. See section 3A for more information.

Note: Please don't bug the authors for copies of the Doom beta. We don't have one. The information in this section was obtained by reading a newsgroup thread.

Section 2 - The Direct Hit

2A. What is a direct hit?

A direct hit happens when the BFG's green plasma ball directly hits a target. The target can be a monster, an exploding barrel, or an opposing player in a multi-player game.

2B. How much damage does a direct hit do?

A direct hit with the BFG will cause a random amount of damage between 100 and 800 points. Keep in mind that these are the base values as stored in the game engine. The actual amount of damage taken by a player is modified depending on skill level. How much is it modified? We don't know.

A note about skill levels: Testing seems to show that weapons always do the same amount of damage to monsters, but that the player objects can absorb the weapons better at lower skill levels. Therefore, it takes more shots to kill a player at lower skill levels, and fewer shots at higher skill levels. This is why some players prefer to deathmatch at the higher skill levels: The frags are quicker that way.

If your target is lucky enough to survive a direct hit, he is still susceptible to damage from the blast area. This happens sometimes in a deathmatch. Since there is a brief pause between the direct hit and the blast area calculation, your victim may go through several stages of fear and elation in the space of one second:

  1. Victim sees the BFG coming towards him (Uh-oh.)
  2. BFG scores a direct hit (D'oh!)
  3. Victim realizes he has miraculously survived (Woo-Hoo!)
  4. The flash damage kills him a moment later (D'oh!)

2C. What are the limitations of a direct hit?

The direct hit is not limited by the same parameters as the blast area. There is no range limit, and the damage does not decrease with distance.

The hard part is that the BFG's plasma ball travels at a fixed speed, and can be avoided by an alert deathmatch player. The reference number for the BFG ball's speed, as stored in the .EXE file, is 25. For comparison, rockets travel at 20 and plasma gun shots travel at 25.

If it seems like this is too fast, and would not be easy to avoid, remember that the plasma gun fires in a continuous stream. The BFG can only be fired once every few seconds. The BFG's green ball is also very bright and large on the screen. All of those factors make it generally easier to avoid in a deathmatch game.

A direct hit in a deathmatch (against good players) is usually the result of luck, or the result of a player that did not know the BFG ball was coming towards him. See section 4 for details of a trick that can help you achieve the latter scenario.

The direct hit can only damage one target. If there are two targets very close together, the green ball can only hit one of them directly-whichever one it touches first.

Section 3 - The Blast Area

3A. What is the blast area?

After the green plasma ball detonates, and after the damage is calculated and deducted from the target that received the direct hit (if any), the area effect of the BFG is calculated. Targets that fall within a specially defined area will take varying amounts of damage.

Simply put, the blast area is like an imaginary 'cone' or 'fan' of 20 damage traces that briefly extends outward from the attacking player. The cone always points in the direction that the weapon was fired. For instance, if you originally fired the weapon in the northwest direction, the cone will always face northwest, regardless of which direction you're facing at the moment of detonation.

Note that this does not mean that the attacker must continue to face in that direction. The attacker is free to turn away from his targets, as long as he moves to a position that keeps this imaginary cone pointed at them. Common misconceptions are that you must be facing either the targets, the detonation point, or the same direction as the weapon was fired. None of those things are necessary in order to inflict damage.

Also note that this imaginary cone has no relation whatsoever to the detonation point. The location of the detonation point is only important for the direct hit (see section 2). Only the moment of detonation is important, not the location. It is possible to have the green ball detonate twenty miles away in a completely different room at a totally different altitude, but the blast can still cause damage right next to you.

The paragraphs above cover the basic concepts of the blast area. More detailed information can be found in section 3D, below.

3B. How much damage does the blast area do?

The 20 traces that make up the blast area's damage cone each do a random amount of damage between 5 and 15 points. Again, these are only the base values stored in the game engine, and may do different amounts of real damage at different skill levels. See section 2B for more info.

Because these traces radiate outward from the attacker in a fan shape, a target will more likely be hit by a given trace if he is close to the attacker. Therefore, targets closer to the attacker will generally take more damage because they are hit by more traces.

If a target is very close to the attacker (for instance, standing right next to him), the target might be within the hit range of all 20 traces. The amount of blast area damage in this situation would be between 100 and 300 points. However, all 20 traces would not necessarily be absorbed by that target, and might move on to other targets. See section 3F, below, for more information on this phenomenon.

This blast damage is calculated in addition to the direct hit damage (if any), making the total possible damage points for the BFG a whopping 1100 points.

A note about random numbers:

A phenomenon known as the 'bell curve' happens when you combine the outcome of multiple random numbers. Players of book-and-paper role-playing games may recognize it. In those games, you would often use three dice to generate a random statistic. In theory, adding the three dice would generate a random number between 3 and 18. But in reality, the actual results would be weighted towards the middle of the range, around eleven. The odds of getting a three or an eighteen are rare because you'd have to roll 1+1+1 or 6+6+6. There's only one possible combination for each outcome. On the other hand, rolling an eleven is relatively easy: 6+4+1, 5+5+1, 3+3+5, etc. If you were to graph the outcome of a thousand rolls, the graph would be shaped like an arc or a bell, with more rolls coming up in the middle of the range of possible values. Hence the name 'bell curve'. The role-playing games use this to make certain random statistics more fair.

This applies to the damage traces, as well, because they are essentially a group of multiple random numbers. For instance, if you hit your victim with all twenty traces, the possible damage should be between 100 and 300 points. But the odds are that the total damage will more likely be around 200 points, due to the bell curve. The odds of doing 100 or 300 points damage in that situation would be extremely rare.

3C. How long does the blast effect last?

Testing has shown that there is a brief time window in which a hapless player can wander into the damage cone after detonation and still take some blast damage.

There seems to be two factors at work here:

  1. There is a brief pause between the moment of detonation and the moment that the damage traces begin to work. This pause seems to have been inserted deliberately by the designers. The exact duration of this pause is not known. Some evidence suggests that the pause is about four-tenths of a second long, but this is not confirmed. It's not known exactly how it affects the trace calculations, but it seems as though all calculations begin after the pause.

  2. It seems as though the traces are not calculated instantly. If a player moves into the damage cone during the trace calculations (after the deliberate pause), he might still take some damage. At the time of this writing, the exact duration of the calculations has not been determined. It is possible that the trace calculations work more slowly when there are many things happening in the game, i.e., when there are a lot of monsters on the screen. However, this has not been confirmed, and we might even be imagining the whole thing. It's possible we're mistaking this for the deliberate pause mentioned above. This question will hopefully be addressed in more detail in a later version of this FAQ.

3D. How exactly does the blast area work?

The blast area is a spread of 20 invisible traces that radiate outward from the attacking player. The damage for the traces is calculated shortly after the green ball detonates against a target or a wall.

The traces radiate outward in an imaginary cone that is roughly as wide as the player's view, i.e., about 45 degrees to either side of the centerline. The cone always points the same direction as the attacker was facing when he fired the weapon. For instance, if you fire the green ball in the southeast direction, your cone of traces will always radiate towards the southeast.

Regardless of how much you run and turn between the time you fire and the time the green ball detonates, the traces will always radiate from your location. Think of it like a tank with a gyroscopically stabilized turret: only the cone's origin point moves around with you, not its direction. The cone's direction remains fixed on the same compass heading.

From a technical point of view, the game engine does not actually keep track of the cone while you're running around. That's just the effect it seems to have. Most likely, it simply stores the vector of the direction of the green ball's flight in a variable. When the time comes for the ball to detonate, the variable is retrieved to begin the calculations for the traces.

Because of this, the cone's direction is based on the direction that the green ball was actually fired, not where you were when you pulled the trigger. As far as the game engine is concerned, you haven't fired it until it actually leaves the barrel of the gun.

Here's a diagram of how it works:

(Diagram of damage cone.)

Note that this diagram is foreshortened. The detonation point would have to be quite far away in order for the attacker to run that far. But the principle is the same, regardless of how far the green ball flies: The damage cone is calculated after the green ball detonates.

When the green ball detonates, the traces are calculated one at a time, using the same criteria for calculation that the engine might use for a bullet: If there is a solid object (a wall, etc.) between the target and the attacker, the trace is harmlessly absorbed by the object. With one exception: In order to hit a target with a bullet, you had to be facing the target. You don't have to be facing your target in order to do damage with one of the traces.

Quick review:

3E. What are the limitations of the blast area?

There is no range limit for the blast area, but the farther a target is from the attacker, the less of a chance it will be hit by a given trace, therefore the less damage it takes.

Because of this, the effective range of the blast area ends up being in the neighborhood of 1000 units. At the outer edges of this range, a deathmatch opponent will only get hit by one trace, taking only 5-15 points of damage. Farther out from that range, it becomes increasingly unlikely that a target will be hit by any traces at all. Of course, larger targets such as spiderdemons have a wider radius, and therefore the BFG's effective range is slightly farther against such targets.

Keep in mind that there is no part of the program that explicitly prevents traces from hitting targets outside the 1000 unit range. It can happen, and does in fact happen, it is simply less likely. For the purposes of learning how to use the weapon in a deathmatch game, base your strategies on the idea that its main effective range is about 1000 units, and you'll be OK.

If you are unfamiliar with the Doom engine's units, remember that a standard teleporter pad is 64 units across. Line up 16 of those and you've got a basic idea of what 1000 units is.

The blast damage is also limited to targets that have an unblocked line of sight to the attacking player. This does not mean the attacker must see the target. It means that the attacker must be in a position where his traces can see the target, i.e., he could see the target if he were facing in that direction.

3F. How many targets can it hit?

The blast area can only hit as many targets as its traces can touch. Since one trace can damage more than one target, you can theoretically kill more than 20 targets. In tests on an artificially created grid of monsters, it is not uncommon for a single shot to kill 25 imps. But in regular game play, rarely are that many targets standing in such a perfectly aligned pattern. Usually, some individual targets will soak up more than one trace, while other traces miss targets completely.

The traces are calculated on a 'first come, first fragged' basis. For each trace, the damage is calculated and subtracted from the target and the trace. Where applicable, any target that dies from the trace is removed from the map. Then the engine moves on to the next target in the line of that trace. When the trace runs out of damage, the calculation routine moves on to the next trace.

Here is how it works:

(Please note: In the discussion below, we refer to 'line of sight' loosely. Remember that the attacker does not need to be looking at his targets to inflict damage.)

In the following scenario, imagine that the attacker is standing in a direct line with several targets (imps, perhaps) lined up in front of him, and the green ball detonates on a wall somewhere:

(Picture of attacker standing in front of a row of imps.)

The first couple of imps are close to the attacker. They crumble, having soaked up some of the traces that are pointing ahead of the attacker. The next few imps are a little farther away, and absorb some more of the traces, but not as many. They absorb fewer traces for two reasons:
  1. because the imps in front of them absorbed some of them already, and
  2. because they are farther away and the traces are more spread out.
But they still die. The next imp gets damaged, but does not die. He has soaked up the last trace that was headed in that general direction. The last imp is not damaged at all because there are no more traces left in his direction.

In order for the above scenario to work, the targets must be perfectly aligned. For instance, in the following scenario, all of the targets take full damage, because there's no one in front of them to soak up traces.

(Picture of attacker standing in front of some scattered imps.)

The one target in the back (Y) is still susceptible because it is not blocked by another target. The attacker can see him through the gap. So, for example, an imp standing directly behind a cyberdemon is fairly safe, but an imp standing next to a cyberdemon is a sitting duck.

The moral to this story is: In deathmatch, do not depend upon other players or monsters to absorb the BFG blast unless they are exactly between you and your attacker. And you'd better hope they're very healthy. In all other cases you take full damage.

3G. How does altitude affect it?

For the most part, it does not. With a few exceptions.

Again, in the discussions that follow, we refer to 'line of sight' loosely. You do not have to look at your targets to hit them.

If a difference in altitude brings your target out of the sight of your traces, then yes, it makes him safe from the blast damage. But if your traces can see any part of him, he takes full damage regardless of how much higher or lower you are than he is.

As far as altitude is concerned, the traces seem to use the same criteria as your view does to determine if the target is visible. In other words, if both you and the damage cone are facing the target, but the target is above the top of the screen, you can't hit him.

But there is a catch. The upper and lower angle limit of the traces seems to be the same as your view would be if your screen was fully zoomed in. For instance, if you are displaying the status bar at the bottom of the screen, your view window is slightly cut off at the top and bottom. Press the plus (+) key repeatedly to zoom all the way in, and you can see what this means. The BFG's traces seem to use the same angle as this full view does to determine if they can hit the target. So if you've got the status bar showing, you can actually hit someone who is off the top of your screen. If you are fully zoomed in, your view seems to be an accurate representation of the damage cone's angle.

If you are standing on a ledge above your target, and you are so close that you can 'touch' him (i.e., you can't step off the ledge because you're bumping into him), your shots will go right over his head and the blast damage will not affect him. This is because, technically, the traces can't see him. Well, if you could look down you would see him, but you can't look down in Doom. Must be those darned restrictive space helmets.

3H. If I am only partially exposed, do I only take partial damage?

No such luck. The only thing that reduces your damage is getting hit with fewer traces. Here is how it works:

If you are hiding behind a decorative sprite (such as a tree or a technical column) you are fully exposed. All weapons in Doom always pass completely through decorative sprites.

If you are peeking over a podium, or partially obscured by a raising lift, or a closing door, and only half or one-tenth of you is showing, you still take the full amount of damage. The traces are calculated based on the game's two-dimensional block map. As far as the game engine is concerned, all of the traces can still hit you.

If you are hiding behind a vertical wall with your rear end peeking out, you might take a little less damage because some of the traces may hit the wall instead. But don't count on it. Tests seem to show that your distance from the attacker is more important than how much of you is exposed. This is an observed phenomenon, not necessarily supported by hard facts. It is difficult to test due to the random nature of the damage traces.

Also remember that what counts as 'showing' may not be what you think. The Doom engine uses the radius of the player to determine visibility. Your player's aspect ratio does not change when you rotate. It also seems as though your radius is slightly larger (in some cases) than the sprite (picture) that represents your player. In tests, it is possible to inflict damage upon a player that seems to be out of sight (no visible pixels) but whose radius is large enough to count as 'visible' to the BFG traces.

3I. What happens if the attacker is fragged before detonation?

The BFG's traces are still active, even if the attacking player is dead. So if you fire the BFG, then get fragged, do not press the space bar to respawn your marine right away. Wait until the green ball has detonated before you respawn.

Here's why:

Even after being fragged, you can still see the action from your fixed point of view on the ground (your 'dead' state). The traces remain active and can still frag an opposing player (hopefully the one that fragged you). The traces will radiate from your dead body's 'eyes'. The traces still follow the same rules, i.e., they radiate in the direction the green ball was fired, regardless of which direction your 'dead view' is facing.

In a previous version of this FAQ, we reported that you will lose the chance to frag your opponent if you respawn before detonation. Several people pointed out to the authors that the statement was in error. The traces remain active even after respawning. Testing shows that the traces do, in fact, continue to radiate from the dead body even after you have respawned in a completely different area of the map. This testing was performed at the prompting of Kirby Nixon, who insisted that it was true. Whaddya know? He was right.

This means that, technically, you don't need to hang around and watch your opponent in order for the traces to work. But Kirby pointed out a good reason to wait for the detonation before respawning: Your dead body's traces can frag you, too! Just because they were once your traces doesn't mean you're immune. If you are unlucky enough to respawn within your dead body's damage cone, you can kiss your butt goodbye.

Of course, the same thing applies to projectile weapons like the rockets and the green ball. It has long been known that those items behaved in that way. But this information about the damage traces is, to the authors' knowledge, new.

Please note: Any projectile kills made by a respawned player (whether by rockets, plasma, BFG traces, etc.) do not contribute to that player's frag count. Killing yourself in this manner does not change your frag count, either. This appears to be because the game engine creates a new instance of the player-object at respawn-time, and therefore 'forgets' to award that frag. In any case, if you wait before respawining, you will get credit for the frag as long as you're still dead. This is another reason to wait for detonation before respawning. Special thanks to John Castelli for pointing this one out.

3J. What about multiple BFG shots?

Each BFG shot is tracked and calculated independently. Testing seems to indicate that the game engine's code is object-oriented, and has no trouble keeping track of multiple blast areas. Each damage cone's direction is based on the direction of its corresponding green ball. The origin point of the damage cone is based on the current location of the marine who fired it (even if that marine is just a dead body- see section 3I for more info).

Section 4 - Deathmatch Techniques

4A. What is considered unfair when using the BFG?

Many deathmatch players moan and groan when the BFG is used successfully against them. 'What a cheap frag, you craven coward!' they shout. Well, they usually use fewer words to express the idea, but that's what they mean. This is usually due to a lack of understanding about how the weapon works.

The purpose of this FAQ is to educate players about how the BFG behaves. If you know how it works, you will know how to defend yourself against it. You will also know how to effectively attack with it. If both (or all four) players have the same knowledge about how the weapon functions, then the BFG by definition is not unfair. If you play against an opponent who does not know how the BFG works, then you should make sure to educate them on its behavior before turning them into paste.

Having said that, the following things are debatable regarding fairness. I'm not saying they are patently unfair, I'm just saying that their fairness is debatable:

In the last two examples, four-player deathmatch tends to cancel out any advantages to those techniques. The remaining three players usually coordinate and attempt to bring down the king of the hill in these situations.

4B. What is the best way to defend against the BFG in a deathmatch?



This requires, of course, that you know where the cone of damage actually is. That, in turn, requires that you know where your attacker is and in what direction he fired the weapon. That, in turn, requires that you know the weapon was even fired at all. Which, in turn, may be difficult against a player who has mastered the Silent BFG trick (See section 4D).

It still helps if you are playing the game with a stereo sound card and headphones. This allows you to hear how far away and in which direction your opponents are. If you think in three dimensions, the sounds you hear in the game will give you a great tactical advantage.

You must understand completely how the weapon works before any avoidance technique would be meaningful. So if you skipped ahead to this section, go back and read the gory details.

With all that said, here are a few ideas. These are just things to try, not necessarily good things in all cases.

4C. What is the best way to attack with the BFG in a deathmatch?


(Sha, nice try.)

This requires, of course, that you know where the cone of damage actually is. So if you looked here first, go back and check out the rest of this FAQ for details.

Anyway, here's some ideas. Not necessarily comprehensive:

4D. What is the Silent BFG trick?

Defending yourself against the BFG pretty much depends on your ability to know precisely when it is being used against you.

If you are fortunate enough to play deathmatch with a stereo sound card and headphones, you know that sound cues are vital to playing well in deathmatch. In many cases, the only way a potential victim knows the green ball is in the air is by the distinctive sound the weapon makes when fired. The headphones can give him directional cues as to its origin, and therefore point the way towards a proper escape.

So if you wish to get the drop on someone, wouldn't it be great if you could put a silencer on that weapon? Well you can. A limitation in Doom's sound code allows you to silence the firing sound of the BFG. Regardless of the 'Number of Sound FX to Mix' that you chose in Doom's setup program, your character can actually only utter one sound at a time. This includes all weapons firing. If you cause your character to grunt, i.e., you jump off of a ledge or press the space bar on a blank wall, you have a brief period while the grunting sound is being played in which you can pull the trigger and no sound will be emitted from the weapon. Your grunt makes a little noise, but it's relatively quiet and is sometimes ignored by your opponents.

While it works well in theory, in practice the trick is hard to perform. It also may be a little unfair. As with all secrets, it definitely makes the game unfair if you don't share this information with your opponents.

As of this writing, there seems to be a small handful of players on the doom newsgroups who use this trick. The first person to submit this trick to the author of this document was John Fedor.

Interesting anecdote: When reviewing a draft copy of this FAQ, American McGee at id Software informed us that they have been using the Silent BFG trick in their deathmatch games since day one.

4E. What is the Level One Strafe trick?

The level one strafe trick is not a deathmatch technique per se, but it's a demonstration of the BFG behavior that educates many folks on how the BFG really works. The act of performing this trick tends to open one's eyes to the amazing possibilities of the weapon. It also proves some points made in this FAQ.

Doug Bora first pointed this demo out to our particular group. Credit for the original version of this demo goes to John Ripley of the UK. The full deathmatch demo file PETALK2.ZIP is the first example of this specific action. Since that time, this has been repeated by many folks on the Doom newsgroups.

PETALK2.ZIP should be available at:

ftp://{INS site}/lmps/doom2/1.9/

where {INS site} = any DOOM ftp site, eg.

Click here to attempt to download the file from now.

(If the link above does not work, please consult the other FAQ files for information on FTP sites that carry doom-related files. The author won't be updating this particular link if it changes.)

How to do this:

This demonstration proves the following: Players who perform this stunt successfully the first time are usually amazed that it actually works. This is also a good practice for using similar moves in real deathmatches.

Section 5 - Submitting Corrections

5A. Common misconceptions

This is a list of the most common misunderstandings about the behavior of the BFG. Please review this list before submitting corrections.
  1. You have to be looking at your target in order to inflict blast area damage.

    This is untrue. The target must be within an imaginary line-of-sight to you at detonation time, but you can be facing away from the target, provided it meets all the other criteria.

    This is an easy mistake to make because you tend to be more accurate in positioning your cone of damage if you keep your eyes on your targets. Especially if you are strafing instead of rotating.

    See section 4E for proof of this.

  2. You have to see the detonation point in order to inflict blast area damage.

    Nope. The detonation point can be completely out of your range of sight, and can be separated from you and your targets by a hundred solid stone walls.

    Again, see section 4E for proof of this.

  3. The location of the detonation point is a factor in the blast damage area calculations.

    Only the moment of detonation is important. The location of the detonation point is not used. See number 2, above.

  4. The location you were standing when you fired, or the location of targets at firing time, is a factor.

    Only the location where you are standing when the blast detonates is important. The compass direction that you fired is important, but not the location where you fired. The traces are only calculated at detonation time. The game engine does not care where the targets are until the traces are calculated.

    Again, see section 4E for proof of this.

  5. You have to be facing the same direction at detonation time as you were at firing time.

    No, the cone of traces extends outward in the same compass direction regardless of which way you are facing at detonation time.

    Again, an easy mistake to make because you tend to be more accurate if you keep your eyes on your targets. Again, especially if you are strafing.

    Again, see section 4E for proof of this.

  6. Your BFG blast can frag someone behind you, but only if they are close enough to touch you.

    You can frag someone behind you if they fall anywhere within the cone of traces. Sure they can be behind you, but they don't have to be touching you. In order to frag someone behind you, you must rotate away from the direction you fired, then maneuver so that your targets are within the cone behind you.

    Having said that, if the victim is standing right next to the attacker, at 90 degrees perpendicular to the cone of damage, they will fall within the cone if they are in front of the attacker's centerline. But if they are truly behind the attacker's cone of damage (behind the centerline of the attacker), they will walk away unscathed.

    This seems to be due to the fact that the player's 'hittable' radius is larger than the player's 'walk into' radius. When you walk up to a player and bump into him, his 'hittable' area is overlapping into your area.

    This is an easy mistake to make when looking at a deathmatch game, where everyone is moving around each other so quickly that it's hard to keep track of the location of the cone of damage. If you really think you fragged someone behind you, it's probably because of one of two reasons:

    1. They were actually next to you and slightly forward of your centerline.
    2. You rotated away from the direction of fire, and the victim stepped into the cone of damage that still existed behind you.

5B. I think the FAQ is in error. How do I get it corrected?

Please go through this checklist before submitting information:
  1. Read the entire FAQ to be sure we did not cover your point in another section. Check the 'Common Misconceptions' section, above, too.

  2. If you have a theory about the BFG behavior, please test it carefully before submitting it. If you can't reproduce the effect under controlled conditions, you were probably witnessing a side effect of one of its known behaviors. Or perhaps it happened in a deathmatch game, where the action is so fast that you often can't keep track of what's going on.

  3. If you think you have tested your theory thoroughly and are ready to submit the theory as proven, please prepare a short description statement that details how to reproduce the effect during game play. Please make sure the description is short and precise.

  4. When you have composed your description message (please make it as short as possible), e-mail it to and wait patiently for a reply.

  5. Note: Do not attempt to send us information for FAQ files other than this one. We do not maintain other FAQ files and we do not echo information amongst other FAQ authors.