The Isle Evrima AI, growth rates and mods

The Isle Evrima has no supported mod loader and no Steam Workshop, so a server cannot be "modded" in the way a DayZ or Valheim server can. What sets one Evrima server apart from another is configuration - how much AI food is on the map, how fast dinosaurs grow, which species are playable, how migrations and day length shape the routine - plus the RCON tooling and moderation around it. The settings that do that live in Game.ini: bSpawnAI, AIDensity, AISpawnInterval and DisallowedAIClasses for AI; bSpawnPlants and PlantSpawnMultiplier for herbivore food; the migration and patrol switches; GrowthMultiplier for progression; and AllowedClasses for the roster. Several of them can also be changed live over RCON. This guide explains what each one does to gameplay and to server load, and gives starting presets for the common server styles.

Installation, ports and the full key list are in the Evrima dedicated server guide. Commands are in Evrima admin commands and RCON.

Mods on Evrima: what exists and what does not#

People arriving from other games ask for a mod list. The honest answer:

• No server mod framework. There is no Oxide, BepInEx or equivalent for Evrima, and no Workshop integration. You cannot add species, items or scripts to the server.
• No client mod support. Players run the official client. Modified client files are not a supported way to add content, and on servers with anti-cheat they are a way to get banned.
• The Legacy branch is a different game. Legacy The Isle had a modding scene and modded servers. Evrima is a rewrite; Legacy mods do not apply, and Legacy servers are not joinable by current clients.

What communities build instead:

That is less than a modded game offers, but it is not nothing. A well-tuned realism server with good moderation and regular events keeps players for months. If a server advertises "mods" on Evrima, check what it means before you assume you can replicate it.

How the AI system works#

AI in Evrima is the food supply for carnivores and part of the ecosystem everyone moves through. It is not a threat layer in the way zombies are in DayZ - the dangerous animals on an Evrima server are other players.

[/Script/TheIsle.TIGameSession]bSpawnAI=TrueAIDensity=1AISpawnInterval=40DisallowedAIClasses=CompsognathusbSpawnPlants=TruePlantSpawnMultiplier=1

AI species are critters and prey animals rather than full playable dinosaurs. At the time of writing the AI classes include Boar, Compsognathus, Deer, Goat, Pterodactylus and Seaturtle; the list grows with updates, so read the class names from your own build's files or tooling rather than from a guide. DisallowedAIClasses is a repeatable key, one class per line, and an unknown class name is ignored silently.

AIDensity: the dial that matters#

AIDensity is both a gameplay and a performance setting, and it is the first thing to reach for in either case.

For gameplay, it decides how easy carnivores find food. At 1, small and mid-sized carnivores can sustain themselves on AI while growing. Push it down to 0.5 and hunting other players becomes the main food source, which raises tension and PvP but also makes the early game harder for new players. Push it up and carnivores grow without meeting anyone, which empties the social side of the map.

For performance, every AI animal is simulated: movement, perception, behaviour. On a busy server, AI is a large share of the main thread's work. If the server struggles at peak, lowering AIDensity to 0.6 or 0.5 is a far better first step than turning AI off or cutting player slots.

Two things to avoid:

• `bSpawnAI=False` to save CPU. It saves a lot, and it breaks the carnivore loop. The map fills with starving carnivores whose only food is players and each other. Use it for test servers and special events, not as a performance fix.
• High density with short spawn intervals. AISpawnInterval is how often the server checks whether to spawn more. Lowering it makes AI refill faster after hunting, at a steady CPU cost. The default is a sensible balance.

AIDensity can be changed live with the aidensity RCON command, and AI can be toggled with toggleai. That is useful for a quick experiment at peak hours: lower density for an evening, watch both the server's load graph and how players react, then put the value you settle on into Game.ini - live RCON changes do not survive a restart. Reading a server load graph explains what to look for.

Plants, migrations and patrol zones#

Herbivores eat plants, and plant spawning has its own switches. PlantSpawnMultiplier above 1 makes herbivore life easier and reduces the need to travel; below 1 concentrates herbivores around the best feeding areas, which is also where carnivores will wait for them. That concentration is how you create the hunting grounds a realism server is built around.

Migrations move the good feeding areas around the map over time:

bEnableMigration=TrueMaxMigrationTime=5400bEnableMassMigration=TrueMassMigrationTime=43200bEnablePatrolZones=True

Read those as three separate systems:

• bEnableMigration turns migration zones on; MaxMigrationTime is how long one lasts, in seconds.
• bEnableMassMigration adds server-wide migration events; MassMigrationTime is the gap between them - twelve hours with the value above.
• bEnablePatrolZones gives carnivores patrol areas that move around the map.

Migrations are what make Evrima's map feel alive: herbivores move, carnivores follow, and the routes cross. Turning them off makes the server more predictable and much more static. They also concentrate players, which concentrates load; a mass migration on a full server is a good moment to check the server is coping. togglemigrations over RCON lets you suspend them temporarily without a restart.

Growth rate and progression#

GrowthMultiplier decides how long it takes to grow from hatchling to adult. At 1 a large species takes many hours of real play; that is the developers' intended pace and the basis of realism servers. Community servers commonly run between 2 and 5.

GrowthMultiplier=2bEnableMutations=TrueCorpseDecayMultiplier=1

What the multiplier actually changes:

• Who can play a large species. At 1, adults are rare and earned, mostly held by regulars. At 5, a player can reach adult in an evening, and the map fills with large dinosaurs.
• The food balance. Adults eat far more than juveniles. A high growth rate with default AI and plant density produces a server full of hungry adults, and the food system was not designed for that. Past about 10, it breaks down.
• Retention. A slow growth rate gives players a reason to come back every day. A fast one front-loads the reward and can leave people with nothing to do once they reach adult.

The multiplier can be changed live with setgrowthmultiplier and switched off and on with togglegrowthmultiplier over RCON. Use that for events - a double-growth weekend is a reliable way to fill a server - and keep the permanent value in Game.ini. Change the permanent value at a wipe, not mid-season. Everyone who spent hours growing at the old rate notices when newcomers do it in a fraction of the time.

bEnableMutations turns on the mutation system, which adds traits that players unlock and pass on. CorpseDecayMultiplier controls how fast bodies rot; lower values leave more food lying around, which softens a low AI density.

The species roster#

AllowedClasses limits which species players may choose. Without it, everything the build offers is playable. With it, only the listed species appear on the selection screen:

AllowedClasses=CarnotaurusAllowedClasses=CeratosaurusAllowedClasses=DryosaurusAllowedClasses=GallimimusAllowedClasses=HypsilophodonAllowedClasses=PachycephalosaurusAllowedClasses=StegosaurusAllowedClasses=Tenontosaurus

Copy the exact class names from the Game.ini your server shipped with or from your RCON tool, never from memory. An invalid name is ignored, and the usual result is a roster missing a species with no error to say why. New species arrive with game updates; check the roster after each one.

Restricting the roster is a balance tool. Common uses:

• Removing a species that dominates your server's player count or fights, until the developers rebalance it.
• Themed servers, such as herbivore-heavy or small-carnivore-only, which play very differently from the full roster.
• Keeping the AI-to-carnivore ratio sane on a small server. Ten large carnivores and ten players is a different game from ten large carnivores and sixty.

updateplayables over RCON changes the roster live. Players already playing a removed species are not usually removed from the game, so use it for planning rather than as an instant fix.

Presets by server style#

These are starting points, not answers. Change one dial at a time from here and watch both the players and the load graph.

Realism servers pair the slow default growth with rules enforced by staff - nesting rules, no killing within your own group, no excessive combat logging - and depend on moderation more than settings. Casual servers trade the long grind for fast progress and need more food to support the adults that results in. Semi-realism, the most common style on public lists, sits between them. Whichever you pick, put it in the server name; players choose servers by style before anything else.

Events built from live settings#

Because AI, growth, migrations and the roster can all be changed over RCON, a server without mods can still run events that feel different from normal play. A few that work:

• Double-growth weekends. setgrowthmultiplier to twice your normal value on Friday evening, back on Sunday night. The simplest event there is, and reliably the best attended.
• Famine. Lower aidensity sharply for an evening and announce it. Carnivores have to hunt players or starve, herbivores herd together, and the map gets very tense for a couple of hours.
• Species nights. Use updateplayables to limit the roster to one or two species for an event - a pack-hunter night, a herbivore-only migration run - then restore it.
• Migration events. Time a staff-run hunt to a mass migration, using togglemigrations to hold one back until the event starts.

Announce each one beforehand with announce, run it at a fixed time, and restore the normal values afterwards - including in Game.ini if you edited the file for it. An event that silently becomes the new normal because somebody forgot to switch it back is how servers drift away from the style their players chose them for.

Performance: what AI and growth cost#

Settings change the load, not just the game:

• AI density is the largest controllable cost. Lower it before lowering slots.
• Growth rate affects load indirectly: more adults mean larger, more complex characters in fights and more food consumption, and a busier map.
• Player count remains the biggest cost overall. MaxPlayerCount above what the hardware sustains at peak is the most common cause of evening lag.
• Migrations concentrate players and AI, briefly raising load in one area.

The general rules - check which resource is actually at its limit, single-thread speed beats core count - are in CPU vs RAM for game servers. On RE:NODE the console graphs memory and CPU against the plan's limits, which is what you need to see whether an AI change made a difference. If the server ever reaches its memory limit, it is stopped and restarted clean rather than left to swap, so a server tuned close to the edge loses progress since the last save. Leave headroom.

Troubleshooting#

Carnivores are starving and the server is all PvP. AIDensity too low, AI disabled, or too many carnivores for the food. Raise density in steps of 0.25.

Everyone is an adult within a day. GrowthMultiplier too high for your audience. Lower it at the next wipe, and announce it.

An AI species still spawns after disallowing it. The class name is misspelt, or the key is under the wrong section header. Check against your build's class names.

A species is missing from the selection screen. It is not listed in AllowedClasses, or its name is wrong. Remove the block entirely to allow everything, then rebuild the list from the shipped names.

RCON changes to AI or growth were lost. Live changes are not saved to the file. Edit Game.ini with the server stopped.

Lag during mass migrations. Concentrated players and AI. Lower AIDensity slightly, or reduce MaxPlayerCount if it happens at every peak.

FAQ#

Can I install mods on an Evrima server?

No. Evrima has no supported mod loader and no Workshop. Servers differentiate through Game.ini settings, RCON tools, Discord integrations and moderation.

What is a good AIDensity for a public server?

Start at 1 and lower it to 0.75 or 0.5 if the server struggles at peak or you want more PvP pressure on carnivores. Avoid turning AI off on a live server.

What GrowthMultiplier do most servers use?

Realism servers keep 1. Semi-realism servers commonly use 2 to 3, casual ones 4 to 5. Past about 10 the food system cannot support the number of adults.

Can I change growth rate without a restart?

Yes, with setgrowthmultiplier over RCON, which is how double-growth events work. The change lasts until the next restart unless you also edit Game.ini.

How do I remove a species from my server?

List the species you want under repeated AllowedClasses keys, leaving the unwanted one out. Use the exact class names from your build's files.

Does turning AI off improve performance?

Considerably, but it breaks the carnivore food loop. Lowering AIDensity gets most of the saving without that cost.