Create mod server: setup, trains and lag

The Create mod runs well on a dedicated server, and it is one of the best reasons to run a modded server at all: a shared rail network and a factory town are better with other people. The setup is ordinary modded Minecraft - Create 6 runs on NeoForge for 1.21.1 and on Forge for 1.20.1, every player needs the same Create version and the same addons, and a small group is comfortable on 4 to 6 GB with Create and a handful of addons. The Create-specific parts are three: addons must match the exact Create version, moving contraptions and large kinetic networks are where the tick time goes, and the server config (create-server.toml) holds the limits - contraption size, belt length, rotation speed, train length - that decide how far players can push it before the server pays.

General modded-server mechanics - Java versions, crash reports, client and server mods - are in running a modded server without the crashes. This guide covers what is different about Create.

Versions, loaders and addons#

Create's version history matters more than most mods', because the jump to Create 6 broke a large part of the addon ecosystem.

The Fabric version of Create has always been a separate port by a different team, released after the Forge version and sometimes with differences. If you want the newest Create, use NeoForge on 1.21.1 or Forge on 1.20.1. Check the project page for the current state of the Fabric port before planning around it.

Create bundles its own libraries - Flywheel for rendering and Ponder for the in-game tutorials - inside its jar in recent versions, so you do not install them separately. If an older guide tells you to add Flywheel, it is for an older Create.

Addons are where version mismatches happen. Common ones include Steam 'n' Rails (more track types and train features), Create Crafts and Additions (electricity), Create: Enchantment Industry, Create Deco, Create: New Age and Create Slice and Dice. Each one targets a specific Create version, often a narrow range. Rules:

1. Pick the Create version first.
2. For every addon, find the release that targets exactly that Create version. Release notes say which.
3. If an addon has no release for your Create version, leave it out rather than forcing an older one in. A mismatched Create addon usually fails at startup with a clear error, and occasionally loads and corrupts something later, which is worse.
4. Players install exactly the same set. Create and all its addons are needed on both sides.

A modpack built around Create - there are many on CurseForge and Modrinth - has done this matching for you, which is a strong argument for starting from one. Modpack servers from CurseForge and Modrinth covers turning a pack into a server.

Setting up the server#

For NeoForge 1.21.1, the installation is the standard NeoForge server install - run the installer with --installServer, which produces a run.sh and a user_jvm_args.txt - then drop Create and its addons into mods/. NeoForge server setup has the step-by-step. Forge 1.20.1 is the same shape.

$ java -jar neoforge-<version>-installer.jar --installServer$ echo "-Xms4G -Xmx4G" > user_jvm_args.txt$ ./run.sh

Java 21 for 1.21.1, Java 17 or newer for 1.20.1. JVM flags and Java versions covers the heap and flags.

Memory, as a rule of thumb from running these servers rather than a figure from the mod authors:

CPU matters as much as RAM. Create's work is on the main server thread, and a world with many running contraptions is limited by single-core speed long before memory. CPU vs RAM for game servers explains why buying more memory does not help a tick-bound server.

The file to know is the server config. On Forge 1.20.1 per-world server configs live in the world's serverconfig folder, so Create's is at world/serverconfig/create-server.toml; NeoForge versions may place server configs differently, so search the server folder for create-server.toml after the first start. There is also config/create-common.toml for world generation, and client configs that do not matter on a server.

The server config limits#

Create's server config is where you decide how big things can get. The values below are the defaults in Create 6; older versions have most of the same keys with some different values.

[kinetics]  maxBeltLength = 20  maxRotationSpeed = 256  kineticValidationFrequency = 60  [kinetics.contraptions]    maxBlocksMoved = 2048    maxChassisRange = 16    maxPistonPoles = 64    maxRopeLength = 384    maxCartCouplingLength = 32[trains]  maxAssemblyLength = 128  maxBogeyCount = 20  trainTopSpeed = 28  poweredTrainTopSpeed = 40

maxBlocksMoved is the important one on a shared server. A contraption is all its blocks moving together as one entity; a 2,000-block drill on a mechanical bearing is a lot of collision geometry being recalculated as it moves, and it is sent to every player in range. Lowering the limit to something like 1024 stops the largest builds and is rarely noticed by normal ones. Raising it on a server with ambitious builders is how you discover the contraption problem.

maxRotationSpeed caps RPM. Lower speeds mean less output per machine but also less work for fans, saws and crushers that process items faster at higher speeds. Leaving it at 256 is normal.

The config also has a disableStress switch. Turning stress off removes the core design constraint - you no longer need to provide enough power - and players then build more machines on fewer power sources, which costs ticks. Leave it on.

Why Create lags, and what to do#

Create is well optimised for what it does, and still capable of filling a tick. The usual causes, in order of how often they turn up in a spark report:

Moving contraptions. Drills, harvesters, elevators, rotating windmills with huge sails, and especially contraptions that never stop. A windmill is a contraption that rotates forever - normally cheap, but a windmill of hundreds of blocks of sails is a large entity rotating continuously. Large sail arrays should be built as several smaller windmills, or replaced with water wheels or steam engines, which are block entities and do not move.

Large kinetic networks. Shafts and cogs propagate rotation through a network. When something changes - a block added, a gearshift toggled, a clutch released - the network recalculates. A factory where everything is one huge network with clutches toggling constantly recalculates constantly. Splitting a factory into separate networks, each with its own power source, keeps changes local.

Item processing at volume. Belts are cheap; items on belts are stored by the belt, not as separate entities. Funnels, chutes, depots and especially fans processing many items at once cost more. Mechanical crafters and deployers - deployers act as fake players - are relatively expensive per action, and a farm of hundreds of deployers adds up.

Item entities. Contraptions that break blocks without collecting them drop items into the world. A tree farm or a drill without storage on the contraption leaves item entities everywhere. Entity cleanup and ClearLag has the commands; the fix is to put storage on contraptions or collect output.

Chunk loading. Create itself does not keep chunks loaded. A factory only runs while someone is near it, unless a chunk-loading mod (FTB Chunks, for instance) or an addon forces it. Every force-loaded factory is a factory that runs all the time. Set a limit per player.

Trains on a shared server#

Trains are the feature everyone wants on a Create server, and they behave better than people expect. A train on a track graph is simulated by Create's railway system when it runs through unloaded chunks; it does not need to keep chunks loaded along its route, and it does not load them as it passes. When it enters loaded chunks near a player, it becomes a visible contraption entity again.

That means a global rail network with dozens of scheduled trains is feasible, and the cost while nobody watches is modest. What costs more:

• Long trains. Each carriage is a contraption. A train at the 128-block assembly limit with twenty bogeys is a large entity whenever players are near it. Lowering maxAssemblyLength and maxBogeyCount keeps the biggest freight trains reasonable.
• Stations and loading. Trains loading and unloading at stations with funnels and deployers are factories, and cost as factories do when the chunks are loaded.
• Signals and junction complexity. Very large signal networks add pathfinding work for each scheduled train. It is rarely the top cost, but a network of hundreds of junctions is not free.

Agree on a rail network plan. Shared trunk lines with agreed gauges and signalling, stations named consistently and a rule about where private branches may join, avoid the situation where every player builds their own parallel track to every destination.

Protection, griefing and claims#

Create's blocks interact with the world in ways land-claim mods have to understand. Deployers act as fake players, and contraptions can move blocks into or out of claimed areas. Whether a claim protects against a contraption depends on the claim mod and its Create compatibility. Test before relying on it: build a drill outside a claim and drive it into one, and see what happens.

FTB Chunks is the common claim and chunk-loading mod on modded servers; it has settings for fake player interaction in claims. Configure them deliberately. On a trusted whitelisted server, it barely matters; on a public one, a drill driven through someone's base is the first grief you will see.

Create also enables some mechanics that are effectively duplication on some versions and combinations of mods. Check the issue trackers of Create and your addons before a public launch, and keep a block logging tool if your loader has one.

Backups, updates and keeping the world#

A Create world is a lot of player effort in a small number of region files, and Create updates touch block and item IDs.

1. Back up before every update of Create or any addon. A clean stop first, so everything is saved.
2. Update Create and its addons together. Never update Create alone while addons target the old version.
3. Read the changelog for removed blocks. Create 6 replaced and changed several components; blocks removed in an update disappear from the world. Some versions provide migration; check before updating a big world.
4. Test on a copy. Upload the world to a second server or a local copy, update there, load the main factories and rail hubs, and look.

What to do when a mod update breaks covers recovery when it goes wrong anyway.

On RE:NODE the Minecraft line ships Paper, so a Create server is your own install: you upload NeoForge or Forge, the mods and the configs through the file manager or SFTP, and set the startup variables yourself. There is no one-click Create installer. What the panel gives you is the boring, important part: backup slots on every plan that restore with a button and are stored off the machine, a schedule for a nightly backup, and a container that restarts clean at its memory limit instead of swapping.

FAQ#

Do players need Create installed to join a Create server?

Yes. Create adds blocks, items and entities, so it is required on both server and client, at the same version, with the same addons. A modpack is the easiest way to keep everyone matched.

How much RAM does a Create server need?

Around 4 GB for Create alone with a few players, 5 to 6 GB with a set of addons, and 6 to 8 GB for a Create-themed modpack. A mature world with big factories needs more CPU before it needs more RAM.

Do Create trains keep chunks loaded?

No. Trains travelling through unloaded chunks are simulated by Create's railway system without loading the chunks. They become visible contraptions again when they reach loaded chunks near players.

Why does my Create server lag when one player is online?

Their factory is loaded. Contraptions, big kinetic networks and item processing run while someone is near them. Profile with spark while that player is online and look for contraption entities and Create block entities at the top.

Can I run Create on Fabric?

There is a Fabric port maintained by a separate team, which has historically lagged behind the main Forge and NeoForge releases. For the current Create version and addon support, NeoForge 1.21.1 or Forge 1.20.1 are the safer choice.