From Halopedia, the Halo wiki
Forge is a multiplayer gameplay mode in Halo 3 that allows players to create map variants by re-arranging the objects in a map. There are many useful tricks and glitches in Forge that allow mapmakers to perform very useful tasks and create very interesting maps; several of these techniques are detailed below. In Halo: Reach many of these tricks will be unneeded as the Floating and Interlocking features will be include in the game.
Tips and Tricks
Unlimited Money Exploit
As the name implies, the Unlimited Money Exploit is a glitch that allows players to completely circumvent the object limits imposed by Forge's budget system.
To perform this exploit, first buy one of every object you plan on using. Set each object aside, press X while hovering on it, and set the Run-Time Maximum to one value higher than the amount of the object placed on the map. Now, you can freely place as many of this object as you want, and the Run-Time Maximum will automatically increment with each new object.
Please note that once you've used up your entire "normal" budget, your budget will start going negative. If, after your budget goes negative, you delete an object after having placed the maximum amount of that object, then you will have to redo the glitch to place more of that object. To redo the glitch, you will have to delete enough objects to get your budget back up to a usable amount. If you don't need an item, set it aside until you're completely finished with your map and you know you no longer need it; then delete it. (A good idea is to set up a "trash bin" to sling objects into if unneeded.)
There is a way to retrieve items that you have lost. These methods include:
It is possible for two players to cooperate and budget glitch a map without placing one of every item on the map—in other words, it is possible to have a budget-glitched canvas map. The method was discovered before August 27, 2008, by players with the gamertags "BuddhaCrane" and "TheCartographer". The players shall be called Person A and Person B; a Grav Lift shall be used as an example of the item to be glitched. The glitch may be conducted over Live or on Local. A guest profile may be used.
Note that the numbers provided above assume that all Grav Lifts have been deleted from the map. Such deletion is not necessary, however.
As with Method A, deleting the last of a budget-glitched item (e.x. the last Grav Lift on the map) will undo the glitch for that item. Furthermore, if the maximum amount of that item has been placed, deleting any of that item will undo the glitch. In both cases, the glitch will have to be re-done—and that is only possible if the budget has not been exceeded.
An alternative method starts by loading an unmodified version of the map. Next, find a weapon that uses energy rather than reloadable projectiles. Place a Covenant energy-using weapon exactly on top of it. The two items' spawn points (teardrops) should align exactly, such that they look like one spawn point. Once done, return to player mode, grab the new weapon, and use all of its energy.
Teleporters of Death
On many maps, you can place Teleporters outside of the level's boundaries without them being deleted. This allows an instant death, or one caused by the The Guardians on Snowbound, Sandtrap or Sandbox. On most maps, however, players entering such teleports will receive the rather inaccurate message that they "fell to [their] death". A specific method of placing floating items makes it extremely easy to place such Teleporters.
It is possible, on maps like Last Resort, to place a Teleporter such that players may use it to exit the level's boundaries without dying. Sometimes, however, when you are entering the Sender Node, it will say "Teleporter is blocked" if the corresponding Receiver Node is placed in certain areas.
To set an object to instantly respawn without any wait time, set the object's Run-Time Minimum and Run-Time Maximum counts (under the object's summary page, accessed with two presses of the X button) to the same number. The minimum count must be as high as it can go for this to work. The object will now instantly respawn when disturbed. (Weapons are an exception, because when you pick them up, they still exist on the map.) You can make an infinite Fusion Coil shower using this technique; it is also useful when attempting to use Trip Mines to overload maps.
Remote Control of Fusion Coil Bombs
With the infinite respawn tool comes a trick that allows you to remotely turn on and off Fusion Coil bombs—groups of perpetually-exploding Fusion Coils. When you have one running on infinite respawn, and it keeps blowing up, if you wish to turn it off, bring up the items menu with X, select Fusion Coil in the scenery object list, hit X, and then set the Run-Time Minimum to at least one below the maximum. The infinite respawn will now be turned off.
A common mapmaking trick is to make several similar-looking rooms and place an intricate network of Receiver, Sender, and Two-way Nodes inside of them, set to a variety of different channels. This can turn a map into a rather difficult maze.
Detailed below is an example arrangement that you can try.
Horizontal Grav Lift
It is possible to create a horizontal Grav Lift that propels players laterally instead of vertically. The process is simple. Start by placing a Weapon Holder on the ground. Then, simply place a Grav Lift (scenery, not equipment) on top of the Weapon Holder. The Lift will begin to rotate, until it eventually straightens out, pointing horizontally.
Please note that you can only place four of these, as you can only place four Grav Lifts. Furthermore, to rotate the Lift, you must rotate the underlying Weapon Holder, and then re-place the Grav Lift atop the Holder.
On Sandtrap, spawn a Crate and place a Turret Case on it. Then, spawn a Receiver Node on top of the stack and delete the objects beneath it. Next, place another crate with two turret cases on top of it and place a sender node on the pile and set it to a different channel than the Receiver Node. Place a Grav Lift on the Receiver Node and test to see if you can reach the Sender Node, and be certain that if you accidentally enter the gravity lift, you can get away before you get teleported off (in Player Mode, with normal speed and gravity) to the left of Elephant where the team without a Chopper spawns in.
Place a Receiver Node on the interior wall, with the illuminated "leg" pointing towards the opposite wall, and set it to the same channel as the Sender Node. Just inside each opening except the roof, place a Weapon Holder with one of the upward-facing extensions facing outside. Place a Mongoose a short distance behind each weapon holder (there isn't room for any other vehicle), making sure that there is enough room so that the Grav Lifts you are about to place will not blast the Mongoose unless you drive it out.
Next, add some Horizontal Grav Lifts using the Weapon Holders you placed earlier. Set the Run-Time Minimum for Grav Lifts to four. Place four Radio Antennas on top of the structure over the opening so that it is covered, and have the ends of each antenna alternate so it should be that on one side of the gap, there are two antenna bases, and the same should be true for the other side. Place a weapon holder on the thick solid part of each radio antenna to stop them from being blown off.
You can also make an effective 'Jail' by using the Horizontal Grav lift trick (this works well if you can forge a 'container open') by placing two horizontal grav lifts facing inwards. This could be effective if you are playing 'cops and robbers'.
The Floating Forge Items glitch allows players to force Forge Objects to hover in midair. In some cases, items must have an (also-floating) inactive Teleporter placed beneath them to stay in midair - sometimes, this flaw even affects immovable items like Double Boxes, though not on Heroic Map Pack maps.
The glitch is commonly used to construct elaborate and unconventional maps and levels - anything from floating Box Forts to raining Fusion Coils.
This is the simplest method of performing the glitch, but it is also relatively error-prone... Movable items floated with this glitch will immediately fall if touched, shot, hit by anything, or even approached when in Edit Mode. However, for things like raining Fusion Coils, this flaw could work to a mapmaker's advantage.
To float an item, simply stack up other items until they form a tall enough tower or pile. Then, place the item you want to float on top of the pile or tower, and delete the entire pile or tower beneath it once the floated item stops moving.
It should be noted that Teleporters floated using this method will never fall, so by placing other items on top of Teleporters that have been floated in such a manner, it is possible to construct elaborate structures in midair.
The second method of performing the glitch is also very easy. Perform Method A (above) on a Teleporter, and then place the desired floating item on top of the Teleporter. The Teleporter will never fall, so neither will the object.
The third method of performing the glitch is still easy, but far less convenient, as it requires you to end the Forge session. Simply spawn the item you want to float, maneuver it into the desired location, save the map, and end the Forge session without moving the item. When you re-enter the map in Forge, the item will be floating, and it can't fall unless you grab it in forge.
If a destructible Forge Object is dropped by a player in Edit Mode, and then destroyed while in midair, then it will respawn exactly where it was destroyed. If an editor, for example, drops a Fusion Coil, and a sniper blows it up in midair, then it will respawn where it was shot.
In Halo: Reach, spawn a weapon and set it as Fixed or Phased. When a player holding it is killed, it will float where it left their hand (not necessarily like it was being used, as they don't drop it immediately after dying).
The final method is to have two players, A and B, should move to the desired location. A should then spawn a sender node and hold on to it. B should spawn a crate on top of the node. After a couple seconds, A should move the node on top of the crate, let go, and after another few seconds, delete the crate. Then, spawn the desired object on top of the node.
The Halo 3 Engine uses a very common physics optimization: if an object is undisturbed for exactly five seconds, physics stop being calculated for it. If the object is disturbed later, physics are recalculated. So if, for example, a Fusion Coil were to remain stationary on top of a Double Box for five seconds, and then the Double Box were to be deleted, then the Fusion Coil would remain in the air.
However, when touched or moved in any way, the Fusion Coil would fall. Furthermore, if a new round or session were to start, the Fusion Coil would fall at the start of the game. Only immovable objects remain in the air, because their physics are only "reactivated" when they are manipulated by a player in Edit Mode.
Here is a list of common ideas that the floating items trick is used for.
The Interlocking Objects glitch, as its name states, allows players to force two Forge objects to overlap and interlock.
To make two or more objects interlock, place the first object you want to interlock and turn off its Placed at Start setting. Make sure the respawn time is long enough for you to place the second object as you want it. You may also want to place another object such as a wall to act as a "guide" to help align the two objects.
Start a new round and place the second object within the area in which the first object will spawn. Once the first object spawns, the two objects should interlock; be sure to set the first object to spawn at start. The next time you start the game the two objects will then be "interlocked" with each other. This method will in fact theoretically work for any number of objects.
Note, however, that objects that have physics calculated (e.x. Crates, Barriers, etc.) may come apart.
Method 2 allows you to interlock objects without starting a new round. The instructions use the process of interlocking a Single Box and a Double Box as an example.
It should be noted that this is more of a "geolocking" method—it will partially force some objects into walls or the ground. The instructions below use a Double Box (in Foundry) as an example.
And the process for putting a Double Box into one of Foundry's walls:
Note that movable objects cannot be interlocked. Attempting to interlock a movable object with any other object will cause the objects to separate, and in some cases, they may violently launch away from each other. This is because physics are calculated for movable objects after they are placed.
This method allows you to make an object go right through another one
1. Rapidly tap Dpad up and the X button while being in the edit mode
2. When the spawn menu pops up while you are in the play mode, spawn the object you want to interlock in an other one
3. Go into edit mode and press the X button while aiming at the object you just spawned and set the respawn rate to Never
4. Spawn the same object that you just spawned using the same method and again, set the respawn rate to Never
5. Press the X button again and set the runtime minimum of the second object to the maximum
6. Grab the object you just spawned and wait until the first object you spawned to kinda glitch into it
7. Then, you should be able to place the object through whatever you want !
There is also another method similar to interlocking called geolocking. Geolocking is the act of interlocking immovable items—such as Fence Boxes or Walls—into the floors, walls and ceilings of maps. As an example, you can use it to bury a Wall half-way inside of the snow in Avalanche.
Movable objects cannot be geomerged for the same reason that they cannot be interlocked.
The phrase "non-solid" here means that collisions are not detected for the object, and hence they are not corrected. This allows the object to be moved through level geometry and other objects. If a player lets go of such an object, it will be frozen in place. However, the object cannot be picked up once it has been placed. Starting a new round allows players to pick up the object, but it also regains its solidity—it will not move through solid objects.
The reason that the object respawns "inside of itself" is because the Run-Time Minimum forces the game to create one copy of the object for every spawn point on the map, but one of the spawn points' Respawn Rates has been set to "Never". By holding a copy of the object (and, therefore, its associated spawn point), a player can evidently force a game to spawn an object anyway, despite the "lack of room".
Interestingly, when an automerged object is dropped and stops being Forgeable, it behaves in a very similar manner to the "Crate" Forge Object, which temporarily stops being Forgeable when it has been significantly displaced.
No-clip merging with turrets
Please read the above sub-article first!
Follow the steps above until you reach the point where you must move the objects (after dummying them). You must move the turrets carefully (Machine Gun Turret or Plasma Cannon) so that you do not break them. Now, in edit mode, grab the respawnable turret. Set the RUN-TIME MAXIMUM to as high as it can go. Now you must find a way to destroy the other turret without dropping the one you have now. Here are some ways to do this:
If done correctly, the turret being held will be come clipless as unmovable scenery in the sub-article above.
When you switch from Player Mode to Edit Mode, your state is preserved. This is a really fancy way of saying that whatever was happening to you in Player Mode will be "paused" until you return to Player Mode, at which point it will continue. As an example, if you are stuck with a grenade while in Player Mode, and you enter Edit Mode before it explodes... the grenade will disappear. But when you go back to Player Mode, it will reappear, and detonate as it normally would.
The following things are preserved—they're "paused" when you enter Edit Mode, and they resume when you return to Player Mode.
Cool Things to Try
Traps and devices