Fallout: Vault 13

Fallout: Vault 13 | Release Date TBA

• Game: Fallout 4
• Development Time: 25+ months (ongoing)
• Mod Page: ModDB

Fallout: Vault 13 is an upcoming modification for Fallout 4 that aims to remake and reimagine Fallout 1 in the Fallout 4 Creation Engine. Our development team intends on bringing the world of Fallout 1 to life in 3D, while preserving the atmosphere that has captivated fans for decades.

Since founding the project in 2021, I have been an integral part of the development team, where I currently serve as project co-lead. Some of my responsibilities as project co-lead include directing our team of over 20 volunteers, handling version control, and monitoring our social media accounts.

In addition to the responsibilities listed above, I am also responsible for the implementation of all quests, dialogue, and new game mechanics. The showcase video below provides a look at some of the quests and dialogue I implemented for Fallout: Vault 13.

Random Encounter System

One of the new game mechanics I implemented for Fallout: Vault 13 is the random encounter system. Instead of using a variation of the Fallout 4 random encounter system, I decided to create a new system from scratch to better fit our needs. The new random encounter system takes inspiration from Fallout 1 by considering the Player’s Luck and Outdoorsman skill values when calculating how difficult a random encounter should be. The random encounter system also allows for dynamic spawn locations, allowing creatures to ambush you anywhere on the map, from any direction.

When the Player enters a new exterior cell, the game rolls for a random encounter. The chance of a random encounter starts at 1%, but gradually increases each time a roll is unsuccessful, resulting in an approximate 15% probability after seven iterations, and a 50% probability after ten iterations, meaning that a random encounter is guaranteed after exploring the wasteland for a short time.

Once a random encounter is triggered, the game checks for the Player’s Outdoorsman skill and Luck values. The chances for each encounter can be found below.

Outdoorsman and Luck Values / Encounter	Outdoorsman 0-25 / Luck 1-2	Outdoorsman 26-50 / Luck 3-6	Outdoorsman 51-75 / Luck 7-8	Outdoorsman 76-100 / Luck 9-10
Encounter 1	2%	0.5%	0%	0%
Encounter 2	7.5%	4%	2%	0.5%
Encounter 3	28%	21.5%	14.5%	9%
Encounter 4	46%	48%	46.5%	40.5%
Encounter 5	14.5%	21.5%	28%	34%
Encounter 6	2%	4.5%	9%	16%

For each encounter, the percentage chances are averaged based on the Player’s Luck and Outdoorsman skills. For example, if the Player has a Luck of 1, and an Outdoorsman skill of 100, there will be a 1% chance of encounter 1 occurring.

Once the encounter has been determined, the game checks where the Player is located to determine which encounter table should be used. For example, the “Desert – Shady Sands” random encounter table will only be used if the Player is located within a certain number of units from the settlement Shady Sands.

When it is time for a random encounter to spawn, an “anchor marker” moves to the Player and faces them. Depending on the encounter, the marker can be located in front of, behind, or on either side of the Player, at a distance of close, medium, or far away. After checking to make sure the Player isn’t looking right at the marker to prevent the NPCs in the random encounter from visibly popping in, the NPCs are spawned in formation, relative to the “anchor marker” from earlier. Once the Player gets far enough from the “anchor marker”, all of the random encounter NPCs despawn and the encounter is considered complete, allowing the game to start rolling for random encounters again.

As of right now, our random encounter system fits our needs well. Depending on how we handle city environments, we may explore predetermined spawn locations for random encounters to prevent issues with NPCs spawning outside of the playable area.