How it works

It rewrites unit definitions before the match starts. Every unit rolls a rarity tier from Common up to Beyond All Reason — 29 steps. The tier scales the unit's stats exponentially: health, damage, range, speed, build costs. A Rare Peewee is a slightly better Peewee; a Mythical one is a different problem entirely.

The roll happens once per match, at load, and is identical for everyone in the lobby.

Every unit starts at Common and keeps escalating one tier at a time while a coin flip keeps coming up heads. That coin is the rarity chance slider — at the default 0.75, three quarters of the rolls climb another step, so the distribution is geometric: lots of low tiers, a long thin tail of absurd ones.

Because it is a chain of independent flips, raising the slider does not shift the curve evenly — it fattens the tail. The expected roll spread bar in the builder computes the real distribution for whatever you have dialled in.

Left alone, a geometric roll can leave a whole faction with nothing exciting. So before the general roll, the mod walks every factory in the live build tree — including the underwater, hover and amphibious ones — picks one combat unit it can build, and rolls that unit with the escalation starting at the min factory rarity (Mythical by default) instead of at Common.

Those units are also exempt from the curse roll. Whatever lab you open, something in it is worth building.

From rarity 5 up, an armed unit also draws an archetype that bends its scaling: Glass Cannon, Tank, Sniper or Brawler for mobiles, Fortress, Watchtower or Suppressor for turrets. A Tank archetype trades speed for health; a Glass Cannon does the opposite.

On top of that it can roll a trait from its archetype's own pool — Phantom cloaks while stationary, Juggernaut adds 60% health for a third of the speed, Siren replaces damage with brutal knockback. Passive buildings roll from category pools instead: mexes, energy, wind/tidal, converters, radar, sonar, jammers, storage.

A slice of combat units — 20% by default — roll cursed instead of rare. They come out weaker across the board but considerably cheaper, and they are marked [Cursed Mk.N] in-game. Set the curse chance to 0 to switch them off.

Beyond All Reason already gives units experience, and experience already improves health and rate of fire. The only per-unit dial a tweakdef owns is the power tag, which is the divisor in the experience formula — so schools are built on it:

• Prodigy learns about twelve times faster and snowballs if it survives.
• Bloodthirsty is fragile but grows fast on kills.
• Ascendant evolves into a costlier unit from the same lab once it has earned enough experience.
• Trophy never veterans and hands the killer a pile of experience, but starts far tougher.
• Conscript is cheap fodder that learns nothing.
• Mentor is for labs and constructors: the builder banks the experience of everything it built and stamps half of it on the next unit off the line.

It rolls one random tech tier — T1, T2 or T3 — at load and locks the buildable combat roster to it. Economy and utility stay available at every tier, so the game is still playable: only combat units, labs and defensive turrets get capped.

On a T2 roll commanders can build T2 labs directly at T1 cost; on T3 they build gantries at T1 bot lab cost and gantries get T2 constructors appended so the economy is reachable. It is optional and lives in its own lobby slot.

Each !bset tweakdefs slot accepts at most 16,384 characters, and the mod is bigger than that. It is split by scope:

• tweakdefs — combat units, armed buildings, constructors.
• tweakdefs1 — passive buildings plus the veterancy schools.
• tweakdefs2 — the optional faction buff.
• tweakdefs3 — the optional tier lock.

All slots run in the same Lua state, in slot order, so the later ones can read what the earlier ones decided. The builder shows a live character budget per slot; if a payload goes over, it will not fit in the lobby field.

No. The mod writes the new names into each unit's customparams (i18n_en_humanname / i18n_en_tooltip) and BAR's built-in Tweakdefs Custom Unit Names widget, which is on by default, applies them. You see [Mythical Marksman Sniper] on the unit with nothing to install.

The old Tweakdefs Bridge is not needed any more and no longer works: current BAR stops user widgets from reading infolog.txt, which is where it got its data. If you installed it, you can delete it from data/LuaUI/Widgets/. If names do not show, check that Tweakdefs Custom Unit Names is enabled in Settings → Custom.

Yes. The tweakdefs string is part of the lobby setup, so every client loads the same code and the random rolls resolve identically on each machine. There is no per-player advantage, and no desync — the definitions are decided before the match starts and never change during it.

PvE rosters are left alone: raptors, critters and the scavenger-named structures are skipped, so their build trees and stats are exactly what the PvE mode expects.

One caveat that cannot be fixed from a tweakdef: the <unit>_scav mirrors are generated by the game after tweakdefs run, so a scav copy inherits whatever its player-side original rolled.

It multiplies one faction's health, speed, damage, range, area of effect and shields by a flat factor, and divides reload by it. It does not touch the rarity rolls at all — it is there for players against a boosted AI, or for deliberately lopsided matches.

That is what the builder is for. Start from a preset — Classic is the shipped balance, Tame is closer to vanilla, Chaos pushes absurd tiers everywhere, Trait hunt keeps tiers rare but makes traits near-certain — then move anything you like. Per-faction floors and ceilings clamp the roll for one faction only, which is the usual way to build a tougher AI opponent.

Payloads rebuild as you type, so the character budget on the right always reflects what you are about to paste.