Instructions
Game Type
Open the Custom Game menu and select "Game Type." In the Assault section, select "Neutral Bomb Assault" from the list as a starting point. Neutral Bomb Assault has the same basic structure as Grifball, making it easier to edit.
Open the "Game Options" menu to begin editing the game mode. Press "X" and enter a custom name to give the new Grifball mode a unique designation.
Leave teams enabled from the Game Options menu and select a number of points to play to in the "Score to Win" section. Open the primary options menu named after the new variant.
Select "Grifball" in the "Sides" menu. Halo Reach added built-in support for the mode with this option. Set the Bomb Arm Time and Bomb Fuse Time to "Instant," and set the Bomb Disarm Time and Reset on Disarm to "Disabled." You may set the Bomb Reset Time according to your preference. This time represents how long it takes an uncontrolled bomb to return to its original position. Press "B" to back out of the menu.
Open the Weapons and Vehicles menu. Set the Primary and Secondary weapon slots as the "Gravity Hammer" and "Energy Sword," respectively. Disable all other options in this menu.
Open the General Settings menu. From here you may set the game time limit and player settings as desired. Grifball generally leaves Friendly Fire enabled, though damage and health settings may change slightly in different variants.
Open the Bomb Carrier Traits section. The bomb carrier in Grifball generally has higher speed and more health than other players, though you may modify these settings as you wish using the Shields and Health, Weapons and Damage, and Movement menus. Press "X" again when finished to save the variant.
Map
Open the Forge menu and select the map you wish to edit. The Forge World map is an excellent choice for Grifball editing due to its larger selection of objects. Change the game type to your newly created Grifball mode and start the game.
Create a large, symmetrical, enclosed space using Forge objects. Grifball maps resemble basketball courts, with a goal at either end. If the map is not completely symmetrical, it will not provide balanced gameplay. Traditional Grifball is played on a large, flat surface, but some variants, such as Mayan Grifball, add additional terrain features.
Place a capture plate belonging to the blue team at one end of the arena. Surround the plate with spawn points for the blue team. Since Grifball is traditionally played with four players per team, only four spawns are necessary. Repeat this process for the red team on the other side of the map.
Place a neutral capture point in the exact center of the arena. This is where the bomb will initially spawn, and where it will return if it resets.
Press "Start" and select "Save As New Map." Give the map a unique name and press "Start" to save the Grifball map to the system's memory.