Gravity Anchors

Placeable anchors that warp local gravity. Mark a block (or place the custom Gravity Anchor item) and it becomes a gravity well. Right-click it to cycle through three field modes, and nearby entities get pulled, pushed, or launched by a capped, TPS-friendly velocity field.

What it does

Every couple of ticks each anchor scans for entities inside its radius and applies a velocity based on its current mode:

Attract pulls entities inward, with the strength falling off over distance. Good for item collection and mob funnels.
Repel pushes entities away.
Launch fires entities up and outward on a timer, so you can build launch pads and traps.

Anchors stick around across restarts. Every velocity is clamped so nothing flies off the map, and busy areas are rate-limited to keep the server smooth.

Creating and using anchors

Look at a block and run /gravityanchor to mark it as an anchor. It starts in Attract mode.

You can also run /gravityanchor item to get a placeable Gravity Anchor, which is a glowing lodestone. Place it to create an anchor. Breaking the block removes the anchor, and in survival it drops the item back.

Right-click any anchor block to cycle the mode from Attract to Repel to Launch. The new mode shows on your action bar with a sound cue.

Commands

All under /gravityanchor (aliases: /ga, /gravity, /anchor).

Command	Description
`/gravityanchor`	Mark the block you are looking at as an anchor.
`/gravityanchor mode <attract\\|repel\\|launch>`	Set the mode of the anchor you are looking at.
`/gravityanchor tune <radius\\|strength> <value>`	Tune the looked-at anchor (radius capped at 32, strength at 5).
`/gravityanchor item`	Give yourself a placeable Gravity Anchor item.
`/gravityanchor list`	List registered anchors (with distance, in your world).
`/gravityanchor remove`	Remove the anchor you are looking at.
`/gravityanchor clear`	Remove ALL anchors. (admin)
`/gravityanchor reload`	Reload `config.yml`. (admin)
`/gravityanchor info`	Plugin info and current settings.

Permissions

Permission	Default	Grants
`gravity.use`	op	Create, tune, cycle, list, and remove anchors; get the item.
`gravity.admin`	op	`clear` and `reload` (includes `gravity.use`).

gravity.use gates all anchor creation and tuning. gravity.admin is a second tier for the destructive and global commands.

Configuration (`config.yml`)

Key	Default	Meaning
`affect-players`	`true`	Whether anchor fields move players at all.
`exempt-sneaking`	`true`	Sneaking players are ignored by all fields.
`max-velocity`	`2.5`	Hard cap (blocks/tick) on field-applied speed.
`task-period-ticks`	`2`	How often the field engine runs.
`max-entities-per-anchor`	`60`	Max entities one anchor processes per run.
`trace-particles`	`true`	Draw the dust ring/field outline.
`launch-interval-ticks`	`30`	How often Launch mode fires its impulse.
`modes.<mode>.radius` / `.strength`	per mode	Defaults applied when an anchor is created or switched to that mode.

Per-anchor tune overrides stick until you switch that anchor's mode.

Compatibility

Works on Paper, Spigot, Bukkit, and Purpur for 1.21.1 through 1.21.11 and the 26.1.x line (verified on 26.1.2), Java 21. Built against the Spigot API only (no Paper-only classes) for portability.

Original concept, an internal test idea, not from a Reddit post.