Fallout 3 Quick any% Guide

Section 1 - Any% and Foundations

SPECIAL Book: Mostly doesn’t matter - get out of screen as quickly as possible.

QSQL -Quicksaving / Quickloading : used to skip NPC actions such as single lines of recorded dialogue and weapon animation. Allows limited damage cancelling. Reloads character, NPC, and object data, but not world physics data (useful for the glitch in little lamplight). Allows clipping
Through walls and objects.

Wall clipping : Done most efficiently by QSQL. When you load a quicksave, the game doesn't begin checking collision detection for the player character's hitbox for a few frames. Since we can move while the game is still transitioning from the previous screen, this allows the player to move far enough into walls to be pushed out the other side once collision detection begins. Corners and complex geometry work best.

COC - Center on Cell : Every map in this engine is made up of cells. In interior cells, when you leave the bounds of the playable area of the interior cell, the game resets you to a set point. This point is often the center of the cell if the developers did not set a place.

Vault 101 COC : the entire opening sequence takes place in a single cell. The transitions to white are not loading screens, but rather mask the teleportation of the player character, the changing of their age and the setting of the stage. When you clip out, the coc point for the opening area is the vault when you escape, but since the game didn’t transition, the stage is not set and NPCs are not loaded correctly.

Speed cripple : Can be done with falling or explosives. This glitch happens because the game incorrectly sets the player character's speed to 160% of normal walking speed. Limbs in Fallout 3 have their own hitpoints. When they fall below a certain percentage, they become crippled, resulting in negative effects on the player character taking place. If your legs fall below 20% health, they will become crippled. In normal gameplay, once that 20% threshold is reached, the game applies the effects in around 4-10 frames (how long exactly is dependant on other physics objects in that cell). However, if you load to a save where the player character walking speed is set to 100% as your legs are being damaged, the effect will be applied to the version of the character from the load. This happens because all damage in Fallout 3 is not instantaneous. All damage is damage over time, including limb damage. If a load occurs while the damage is being applied to the legs, the legs will become crippled during the screen transition and the game will load the character having both limb states. The physics engine will interpret this as having both 60% walking speed and 100% walking speed, thus giving the character 160% walking speed. If the load occurs only a few frames too early or late, the game will not overwrite the original walking speed, but rather stack the walking speed of two crippled legs, or 60% OF 60%, which is 36% of normal walking speed. In addition, if the animation is the only effect that applies, and the speed does not change, this happens because the load was too early or the game finished adjusting the cripple speed before the load finished, but before the game set the character animation. Getting just the animation usually means the load was too early. Explosives tend to be more consistent because their damage is less variable when you have a setup. Fall damage is inherently somewhat random because of the way the game calculates gravity and impact force.

Movement over land : In Fallout 3, the most efficient way to move across land is to keep your feet on the ground. Not only does this mean not jumping (with a few exceptions), but also not becoming at all affected by gravity. If you walk off a steep slope and become airborn, your speed changes to a gravity affected fall. Jumping can be more efficient in certain situations, such as a very specific (and rarely occurring) angle of slope, cornering when near a rounded wall, and jumping over very uneven terrain such as rubble, debris, or small physics objects such as bones or buckets. You can also get a speed boost from landing on the edge of a gravity affected object and getting pushed forward. The grade of armor you wear also affects movement speed. The heavier the armor you wear, the slower you go (5% reduction per armor grade, up to 15% reduction)

Movement through water : The player character moved through water at a reduced rate, even when utilizing speed cripple the player moves at the same speed. The most efficient way to move through water is on the surface.

Swimming in fake water : The player has four physical states that are saved in the world’s physics data. Falling from a the ground (walking off a slope), falling from a jump, swimming in water, and null (moving across the ground). As stated, the player’s physical state is saved to the world, which doesn’t change between loads as long as the loads occur within the same cell. In Little Lamplight, the OOB swim takes advantage of this by using the water in Eclair’s kitchen area. After clipping out of bounds, you fall into water. If you save while in the swimming physical state, then swim out of the water, you’ll still be swimming, but the game also a “buoyancy” attribute which does not load under normal gameplay conditions if you swim out of the water. In order to swim out of bounds without sinking, the game must store a number that represents the water’s depth in relation to the player character. If you load save in water, then swim out of the water out of bounds and then load, the game cannot identify a change in physics state (as you were technically in water before and after the load) and since cells normally only have one depth of water, the game sets a buoyancy number to the cell’s character physics. This allows you to swim out of bounds as iif you were in real water.

Quest sequence breaking : quests in Fallout 3 can be started on any objective. The quest in Vault 87 to find the GECK is called “finding the garden of Eden”. Without this quest, we cannot continue to the end game because it triggers a change in state for Col. Autumn. In order to get this quest, we use an optional objective to free Fawkes. We do this using the emergency cell release door. This allows Autumn to stop us after we pick up the GECK.

Third person item interaction : when in third person, the game uses an entirely different interaction hitbox for the player character that is in a different place because of the nature of the over the shoulder perspective. The interactive hitbox is located behind the model of the player character. When in third person, if you swing the camera around into certain positions, the interactive hitbox can clip through objects, allowing the player to interact with objects through walls and other objects.


NPC dialogue/quest states : NPC’s have quest stages, just like the player character. This can affect what dialogue pool and choices the game pulls from. Certain dialogue options are required to advance quests, and quests are universal for all NPC that a quest may affect. Col. Autumn is affected by almost every Main Quest. His location changes based on which stage the player character is on in the main quest. This is important because in order to end the game, we must get Autumn to confront us in Jefferson Memorial. The last three quests done in the any% run are all necessary to get Autumn to the Memorial building with the endgame dialogue. A rare glitch can cause him to have the wrong dialogue because the game mistakenly increments the quests stage twice. This causes a softlock.

Invisible barriers and 3d mapped collision : Most objects in the game are clippable, however, the extent to which they are clippable is determined by a number of factors. Invisible barriers exist in many places in the overworld outside of the normal playable area. They exist because they are part of the geometry of a premade asset that isn’t completely mapped, or only mapped on one side. There are also invisible barriers that are designed to be invisible. These barriers are different than those part of a premade asset such as a building. Designed invisible barriers are 3d-mapped. Most other barriers in the game are merely 2d-mapped. The difference is in the way the game calculates collision. In 2d mapped surfaces, a wall has no depth, it is merely a plane with x and y coordinates. That means, in order to clip through a wall, the player character’s hitbox simply needs to get more than half way through the plane. Invisible barriers that are 2d mapped are harder to clip through merely because it’s harder to find the appropriate angle of approach. 3d mapped barriers are not simply a simple x,y plane. They also have stacked depth. There could be as many as two or three or more stacked planes, each being separated by only a few in-game units. Because collision is calculated on a per-point basis, the more stacked planes there are, the more points the game calculates for collision. This means that in order to clip through a 3d-mapped wall, the player character must make it more than half way through the outermost plane. This becomes difficult because each plane reduces the player character’s potential energy. Examples of 3d mapped walls in the any% run include: the space above the rubble in the upper level of the atrium in V87, the chamber surrounding the GECK in the GECK room (which has textures mapped for 2d collision on the inside surface and outside surface, but is actually a series of 3 stacked 2d meshes), The door to Eden’s stairs in Raven Rock, the radroach and target area in the “Big Game Hunter” section of ten year old V101. Examples of invisible 2d mapped barriers in any% include: Out of the meshed area between Greyditch and The Citadel, the “floors” on the roof after the Eden door clip, various parts of the V101 opening cell that are mostly OOB.