Crashy! 1.3

Four small things, three of them about how a crash meets the world it lands in.

Added

Cobweb stops a physics object, the way it stops you. A launched house going through a web at eighty metres a second and not noticing is the sort of thing that makes the physics read as a separate game running next to Minecraft. A body in cobweb now has its speed dragged to a quarter horizontally and a twentieth vertically every tick, which is exactly what vanilla does to a player, and its spin is dragged with it — an object that keeps tumbling inside a web looks worse than one that keeps moving.

Bodies bigger than a 4096-block box are not checked. The scan is per body per tick and has to be bounded somewhere, and a cobweb does not plausibly stop a cathedral either.

cobwebStopsObjects and cobwebDrag in the config.

A charge going off leaves the ground burning. Vanilla TNT does not normally start fires, but a crash that sets off two dozen at once and leaves a clean crater has always looked wrong. Spots around each charge that could hold a fire on their own now catch, at a third by default: never floating, never on water, and the whole crash shares one budget of forty-eight, so a chain does not set light to the county.

Fires are never lit next to a charge that survived the sweep. Fire would prime it, and a primed TNT is a vanilla explosion — which deletes the blocks around it. The whole reason this mod consumes charges by hand is so that never happens.

blastFireChance in the config; 0 turns it off.

Fixed

"Received a sub-level movement packet for a non-existent sub-level", by the hundred. Sable sends body creations and body movement over two different transports, so a burst of creations lets the movement stream overtake them, and the client logs that line once per body per tick until it catches up. 1.2 made this easy to hit: structural blocks let one activation create up to 256 bodies in a single tick.

An activation now hands the physics engine eight objects a tick and queues the rest, so the two streams stay in step. objectsPerTick in the config if eight is the wrong number for your connection.

This does not remove the race from Sable, it stops us walking into it. If the line still appears in quantity, the next place to look is debris: a big crash creates hundreds of one-block bodies at once too.

Notes

On TNT going off from a nudge: that was fixed in 1.2 — minDetonationSpeed, 24 m/s by default, below which no charge goes off however close it is. Re-checked this release: the speed gate covers every path a crash can reach a charge through, including the chain that spreads to neighbouring ones, since they all come from the same sweep. If you are still seeing charges go off from a light touch, the value in your world's serverconfig/crashy-server.toml is the thing to look at — config files written before 1.2 keep their old contents, and new defaults never overwrite them.

Existing worlds pick up the two new sections with their defaults on first load.

Crashy! 1.2 — Schematics, Scaffolding, and Crashes That Hurt

For Minecraft 1.21.1 / NeoForge 21.1+. Requires Sable 2.0.0+ and its dependencies.

The short version: builds are now something you can save to a file, hand to a friend, and rebuild brick by brick — or have a machine build for you. Platforms can hold several objects that come apart separately. And a launched house is no longer scenery to whatever is standing under it.

Schematics

Blueprints are gone; schematics replace them. Same item, same recipe, same registry name, so a blueprint you already own still works — but what it does is different.

• A schematic is a .nbt file in a schematics folder, in the vanilla structure-block format. It opens in a structure block, in Create, in Litematica's converter, and anything those write loads here.
• The folder is yours, not the server's. Save a build on somebody else's server and the file lands on your disk, where you can actually do something with it.
• The Schematic Table shows you the build turning slowly in the corner, takes a name for it, and writes it. Stood on its own instead, it lists your folder — pick a file with the mouse wheel, feed it a blank, and it writes a schematic. The progress bar is bytes actually delivered, not a timer.
• Holding one shows the hologram. Right-click a block face to pin the build where it should go. Blocks you have already placed drop out of the ghost as you work, so what is left of it is what is left to do.
• In survival there is no Build button. The hologram is the plan. Its Materials page lists every item the build costs against how many you are carrying — counted as items, not blocks, so a door is one and a double slab is two.
• In creative one button puts the whole thing down at once, already glued.

The Schematic Cannon

The survival answer to a four-thousand-block build. Pin the schematic, drop it in the cannon with some gunpowder, stand chests around it, press go.

It works up from the bottom row, takes each item out of the containers beside it, glues everything it places, and steps over anything already standing rather than clearing it. Run short and it stops, shows you the item it wants, and carries on the moment you supply it.

The Structural Block

Scaffolding that glue runs through but physics does not.

It bonds to its neighbours like any block, so one activator still reaches everything standing on it — and then stays exactly where it is while whatever was resting on it lifts off as its own object.

A platform with four houses used to be one enormous rigid body. Now it is four houses you can throw at each other over a platform that stays put and cannot be broken by the crash.

Crashes hurt what they land on

A launched house used to go through a crowd of zombies without leaving a mark. Damage now comes off the same blast force that blocks are weighed against, so it already accounts for how heavy the object was and how fast it was going — about five hearts for a single block at full launch speed, far more for a tower. It falls off with distance, throws you clear, and goes through an ordinary damage source, so armour and resistance work normally. Fast-moving debris hurts on the way past too.

Independent of the destruction mode on purpose: Indestructible is a promise about the world's blocks, not about you. There is a toggle on the F7 screen, in the config, and a game rule.

What a crash may break is now a datapack's business

Four block tags — indestructible, fragile, reinforced, explosive — decide what survives, what shatters early, what holds, and what goes off. Bedrock, barriers, spawners and vaults are spared out of the box. Spawn protection is respected. Two game rules, crashyDestruction and crashyEntityDamage, switch the whole thing off per world.

Everything else

• Gluing an area, the way Create does it. Right-click two opposite corners; a green box follows your cursor and turns red the moment the selection is one the server would refuse.
• Glue never breaks blocks. Left-click takes the glue off instead, which is where a hand goes to undo something.
• TNT needs a real hit. Below 24 m/s nothing goes off, however close it is — brushing a stack of TNT while parking an airship should scuff it, not level the area.
• Water and lava behave: a crash into water makes a very large splash instead of a crater, and lava sets the crater alight.
• Seven advancements, from picking up glue to landing a hit at sixty metres a second.
• New sounds for the activator, the charge and the table.
• New Launcher texture.
• Settings are in the mods list. Mods → Crashy! → Config, alongside the in-game F7 panel.
• English and Russian throughout.

Notes for updating

Existing worlds keep their settings and pick up the new hurtEntities default, which is on. Turn it off in [damage] before first load if a world should stay as it was.

Config files already written keep their old values — new defaults do not overwrite them. If a number mentioned here does not match what you see, it is in your serverconfig/crashy-server.toml.

The schematics folder is made the first time something is saved, next to options.txt in your own game directory. Drop .nbt files in and they appear in the table's list within a couple of seconds.

Sable is an intrusive, mixin-heavy mod and can conflict with other mods that touch world rendering or chunk handling. If something breaks, check whether Sable alone reproduces it first.

Crashy! 1.1

Destruction is no longer something only the launcher can cause: anything with physics that comes down hard now breaks, Create: Aeronautics airships included. Damage depends on what actually hit you, big crashes no longer take the server down, and three crashes are gone.

Added

Anything with physics crashes, not just what you fired. An airship that loses its lift, a build you switched physics on and simply dropped, a contraption another mod is moving — all of it now breaks on impact the same way a launched object does, and digs the same craters.

There is no dependency on any of those mods. Everything Sable simulates is a sub-level, so this mod watches sub-levels; whichever mod built the thing is not its business. Create: Aeronautics is built on Sable, which is why its airships are covered without a line of code that knows they exist.

An object is picked up once it is heavier than 8 kg — roughly a kilogram per block — and moving faster than 7 m/s. Both numbers, and the switch that turns the whole thing off, live under [unlaunched] in config/crashy-server.toml. The speed only has to rule out setting something down: how much a hit actually breaks is decided by mass and speed together, so a heavy airship at cruising speed digs a real crater, while a small build at the same speed does not reach the minimum crater size and nothing happens at all.

After breaking something, an object is left alone for five seconds before it may crash again. Otherwise a hull grinding along a slope would crash on every tick of contact.

"Debris lies for" on the F7 screen — how long shards stay as physics blocks after coming to rest, from 0 to 120 seconds, ten by default. Set it high if you want the wreckage to stay put.

Changed

Damage scales with mass, not just speed. A single block and a 400-block tower travelling at the same speed used to dig identical craters. Crater size and breaking force now both come from kinetic energy, so at full launch speed:

Crater volume scaling with energy is roughly how it works in reality, and it happens to give the numbers the game wants.

The force column only bites in Realistic mode, where it is weighed against each block's blast resistance. Instant mode breaks whatever is inside the radius by definition, obsidian included.

Bedrock is never destroyed, in any mode. Nor is anything else with a hardness of -1 — barriers, command blocks, end portal frames, structure blocks. They are skipped before any force is calculated.

Objects keep going after breaking through. Something with enough behind it to punch through a floor stays tracked and keeps breaking what it meets instead of being written off after the first hit, up to three impacts. Each one is weighed on what is left of the object, so it digs less as it sheds blocks, and impacts are spaced six ticks apart so ploughing through a floor reads as one crash rather than one per tick of contact.

One launch may break 500 blocks in total, shared across every impact it makes. Per-impact caps alone could not bound this: an object going through several floors simply multiplied the work by the number of floors.

Large crashes are spread over time rather than done at once. A 400-block build hitting the ground used to ask for over five hundred separate physics bodies inside a single tick — each one a Sable plot, a chunk and a rigid body — and the server went down under the allocation. Shattering is now queued and processed at a fixed budget per tick, so the crater forms over about a second.

There is still a ceiling on how much debris may be alive at once, but reaching it no longer throws the rest of the crash away. The oldest shards are settled back into the world early to make room, which keeps the number of live bodies exactly where it was while letting the next crash through. Before, for as long as a crater took to settle, nothing anywhere in the world could break — you could throw a house at a wall in that window and watch it bounce off.

Craters no longer heal themselves seconds after the hit. Debris lies where it landed for the configured time, and is thrown clear hard enough that it does not simply drop back into the hole it came from.

Fixed

Large objects registering no impact at all. Impact detection swept the whole volume of an object's bounding box, and gave up — reporting that nothing had been hit — once that volume grew past its scan budget. An airship's bounding box passes that budget on its own, so a ship could come down on solid ground and land without a scratch. Only the faces travelling forwards are scanned now, which makes the work depend on how wide an object is rather than how big it is, and every such face is scanned rather than only the one leading most strongly. A ship easing down as it flies is checked along its underside and its nose, so the mountain in front of it counts.

RuntimeException: Body has been removed, taking the server down mid-flight. Removing a physics body only flags it; Sable clears flagged bodies out in the middle of its physics tick. That tick begins by unloading bodies whose chunks have gone away, and unloading one serialises it together with every body its bounding box touches — without checking whether those are still alive. A crater is exactly that arrangement: dozens of overlapping shards, several of them retired every tick. The flag is now never allowed to outlive the tick that set it.

Rapier native panic: No center of mass for body!, usually followed by PoisonError. When an assembly came out with no usable mass, this mod declined to use the result — but by then the body was already in the physics scene, and Rapier's next step aborts the entire process over it. Such a body is now handed straight back. The PoisonError further down the log is the second failure, the poisoned lock, not the cause.

Notes

Existing worlds keep their current settings; a new world starts from settleDelayTicks in the config file.

New icon, while I was at it.

If a big crash still stutters on your hardware, lower shattersPerTick — the crater takes longer to form but each tick does less work. If you have headroom and want bigger craters, raise maxBlocksPerLaunch and maxDestructionRadius together: raising the radius alone will just run into the launch budget, and raising the block caps alone will just run into the debris ceiling.

If airships break more easily than you would like, raise unlaunchedMinSpeed. If they should never break unless you fire them yourself, set crashUnlaunchedObjects = false.

Crashy! 1.0

First release. Minecraft 1.21.1, NeoForge.

Crashy! is a survival toolkit for Sable, the sub-level physics library. Sable gives Minecraft real rigid-body physics but deliberately adds no way to reach it in-game — this is that way. Glue a build together, switch on physics, then pick it up and throw it at something.

What's in it

Construction Glue — bonds blocks into one rigid structure. Hold it in your off-hand and every block you place is glued to the ones it touches; glued blocks are outlined while the glue is in your hand. Glue is stored per-world and survives reloads.

Physics Activator — turns a glued build into a live rigid body, on an empty-hand right-click or a redstone signal. Right-click an existing object with the item form to switch physics back off: the build settles into the world and stays glued, so you can activate it again.

Launcher — right-click an object to grab it, hold to charge to power 10, release to fire. Full charge throws at about 80 m/s.

Build Saver + Blueprint — a table that records the build attached to it, and a reusable blueprint that stamps it out anywhere, already glued. Pasting skips occupied spots instead of overwriting them.

Destruction settings on F7 — three modes, changeable at any time:

• Instant — everything inside the blast radius shatters, whatever it is made of
• Realistic — impact force is measured against each block's blast resistance, so a power-8 hit scatters planks across the whole crater but only chips cobblestone near the middle, and obsidian is untouched
• Indestructible — nothing breaks; objects still fly and bounce

Plus sliders for block toughness, crater size, debris scatter and launch speed, and toggles for world destruction, TNT and debris settling. Settings live in the world and are shared by everyone; only operators, or the host of a single-player world, can change them.

TNT — a crash sets off any TNT it reaches, instead of a vanilla explosion. The block is removed by hand, so the surroundings are not deleted: they survive and get thrown much further. Chains up to 24 charges per crash.

Impacts — custom crash audio in three variants, shrapnel made of the blocks that actually broke, a ground-hugging dust ring, and sparks that scale with the hit. Debris settles back into ordinary world blocks once it comes to rest.

Recipes for everything, and English and Russian translations.

Requirements

• Minecraft 1.21.1
• NeoForge 21.1.0+
• Sable 2.0.0+ and its dependencies (Veil, Forge Config API Port)

Needed on both the client and the server, and the versions have to match. Crashy! registers blocks, items and network channels, so a client without it — or with a different version — will be turned away at the handshake.

Worth knowing before you install

Sable is intrusive. It makes heavy use of mixins and is prone to conflicts with mods that touch world rendering or chunk handling. If something breaks, check whether Sable on its own reproduces it before reporting it here.

Switching physics off snaps the build to the grid. Positions are rounded and block states are kept exactly as they were, so a tilted object comes back upright and, say, a staircase keeps the facing it had before launch. Matching block rotation to an arbitrary quaternion would be guesswork, and a build that returns subtly rearranged is worse than one that returns straight. Anything with nowhere to land drops as an item rather than vanishing.

Large objects only break where they were hit. Past the debris cap, the impact region breaks off and the rest stays one body. That is deliberate — cheaper, and it looks better than a tower exploding into confetti.

There are limits, and they matter. Every shard is a separate rigid body in Sable's pipeline. The defaults cap a single crash at 220 world blocks and 320 debris pieces, an object at 8192 blocks, and a blueprint at 4096. Raising them a lot on a busy server will cost you tick time.

Debris settling is on by default and should stay on. Turning it off leaves every shard as a live physics body forever.

The glue outline covers 28 blocks around you, up to 2048 blocks at a time. A very large glued structure will not be highlighted all at once.

Configuration

Most of it is on F7. The file config/crashy-server.toml holds the hard limits and the starting values for new worlds — glue group size, blocks per object, blueprint size, hold distance and charge rate, impact threshold and crater radius, TNT blast figures, and how long debris waits before settling.

If shards look like they snap back a second after a crash, raise debrisScatter: a shard that never moves counts as settled and gets written back exactly where it broke off.