Illegal Placement

Place blocks in states vanilla won’t let you — a lever in mid-air, half a bed, a fence that connects to nothing — and keep them that way. No commands needed: press B, aim, click.

The server needs the mod. In singleplayer the client is enough. Fabric builds need Fabric API (any version for your Minecraft version).

Build mode

Key	Action
`B`	Toggle build mode
Right click	Place the held block without validity checks
Left click	Remove the block, no neighbor updates, no drops
Mouse wheel	Move the target nearer / farther, also through air (Shift = fine steps)
Middle click	Pick the block with its exact state (creative)
`G`	Open the panel for the aimed block or entity
`H`	Placement guide on / off

All keys are rebindable.

The panel

Every block state property on a button: left click for the next value, right click for the previous. Two switches underneath:

Lock state — the block ignores shape updates, neighbor updates and survival checks. It stays exactly as placed.
Freeze time — no random or scheduled ticks: no falling, growing, decaying, spreading.

Item frames, paintings and armor stands get a panel too (Fixed, Invisible, ShowArms, Facing, …).

In build mode the outline of the aimed block shows what the next update would do to it: orange means it would drop, be reshaped or switched by redstone — lock it if it should stay. Green means it’s locked.

Litematica on servers

Set commandNameSetblock = ipsetblock and commandNameFill = ipfill in Litematica’s settings. Pastes then keep every illegal state, lock what needs locking and freeze what would fall.

Config

config/illegalplacement-server.properties: permission level, creative only, max reach, fill volume. Client options are in the Build Settings screen (press G while aiming at air).

Known limitations

Freeze time doesn’t stop block entities (furnaces, hoppers).
Display entities and markers can’t be targeted.
Since 1.21.6, G is also vanilla’s Quick Actions key; both work.

Illegal Placement

截图

介绍