Build and Kill Zombies Supports Machine: Roll Pool, Odds, and Luck
How the SUPPORTS machine works in Build and Kill Zombies: the two-machine roll split, rarity bands, roll controls, luck upgrades and boosts, and how rolled pieces mount on your car.
The SUPPORTS machine rolls weapon and defensive support pieces with cash earned from runs — and it is a separate machine from the CAR PARTS station. Support pieces are not bought directly; two separate machines handle all rolling, and this split lets you target the exact bottleneck you have instead of gambling across every category at once. Early income is split between the two machines, so spreading rolls evenly across all categories tends to leave you with a mediocre car in every respect. A full item-by-item SUPPORTS pool with confirmed costs and per-item drop rates is not currently documented — the result card's displayed odds are the in-game reference — but everything below covers what is known about how this machine works.
Rarity bands and where luck applies
Both machines draw from the same shared rarity system:
| Rarity band | What it typically yields | Does luck help |
|---|---|---|
| Common | Baseline blocks, wheels and fuels that fill out a starter car | Marginal — this is the floor, not the target |
| Rare | Stronger engines, wheels and weapon mounts that carry a mid-game run | Yes — the main target of Luck I and Luck II |
| Epic | High-tier parts worth rebuilding a blueprint around | Yes — where stacked luck and boosts matter most |
| Legendary | The rarest rolls in the game, the reason luck stacking exists | Yes — the band every luck upgrade is aimed at |
Rarity bands are documented for both machines combined; individual support items cannot be assigned confirmed rarities except where a guide states one.
How rolls are made
- Q picks a category at the roll machine.
- CONFIRM locks the selected category.
- E rolls and shows the result's rarity plus odds on the result card.
- Odds are displayed on every result, and duplicates accumulate as usable spares instead of vanishing.
- Both machines use identical interaction, so nothing new has to be learned when switching machines.
Luck skills and boosts
Luck upgrades apply to both machines at once. Luck I improves roll outcomes at both machines; Luck II stacks a second layer of the same bonus onto every roll, gated behind Luck I. Gold Roll I sits at the expensive end of the tree, costing thousands of cash. Luck improves odds rather than guaranteeing results — exact luck math is not documented, so a bad streak remains possible after every upgrade.
Paid boosts stack on top: Server Luck (39 Robux, 15 minutes of doubled server-wide luck) and permanent 2x/4x Luck (109/229 Robux) affect all rolls regardless of which machine you are using.
Mounting rolled pieces
Rolled offensive and support pieces attach in Build Mode via the WEAPONS tab, and placement determines whether they work. A Glass Cylinder gives contact damage on anything touching the bumper and is cheap enough for a starter chassis front face. A Shredder is a spiked roller mounted low on the front so it contacts the ground line of the wave. A Crossbow is a ranged weapon, mounted forward-facing with clear line of sight past the chassis edge. A mount fitted to the roof or rear may never touch a zombie, which reads as a broken weapon rather than a bad build.
Dedicated single-item roll stations also exist — including a Crossbow station and a Glass Cylinder station — so you can target one piece instead of gambling on the whole category.
Known price examples
Roll prices scale sharply with usefulness: a Glass Cylinder sits at the bottom of the pool at $15, while a Shredder — also listed as Uncommon — costs $250. Rolls stack duplicates (e.g. x5 Glass Cylinder), and extras are not wasted because wider builds need more cheap filler parts than expected. Treat these price examples as guide-reported rather than officially confirmed, and verify current costs on the result cards in-game before spending.