Simple Block Physics Fabric
Simple Block Physics Fabric makes unsupported blocks fall, so a structure with no vertical support can collapse under its own weight.
What it does
When a block is removed or placed, the mod checks whether the blocks next to it still have support. Blocks that lack vertical support within a range set by their hardness become falling entities and drop until they land. The check is a recursive search that runs only where a change happened, which keeps the work limited to the affected area rather than every loaded chunk.
The mod brings this behavior to newer Minecraft releases, written by jake404notfound and credited to Ferrin-Ember as the original author. It is published for Fabric only, for 1.21.11 and 26.2, with 1.1.1 for 26.2 as the latest file. Worlds should be backed up first, since structural collapse can destroy builds that are not meant to fall.
The mod works on either side, and neither the server nor the client needs it. The source code is public, and the code is released under the MIT License.
Key features
Cave-ins and collapsing structures
Unsupported stone and other blocks break loose and fall, which produces cave-ins and collapsing ceilings.
Unsupported sky bases
Floating builds without vertical support lose their blocks, so bases attached only at the edges do not stay in the air.
Configurable support strength
Options set how strongly blocks support each other and how many iterations the recursive check may run.
Need-based updates
Checks run only when a block is placed, interacted with or changed next to another block, rather than on every tick.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
How it compares
Cave-Instability is a Fabric mod for 1.21.1, under All rights reserved, and it needs both client and server. PhysEx (Water Physics Overhaul) covers Fabric and Forge for 1.16.5 – 1.21.11 and is released under the GNU General Public License v3.0 only, but it runs on client and server and focuses on water. Collapsing Caves runs on Fabric, Forge and NeoForge for 1.20.1 – 26.3 under CC0 1.0 Universal, and needs client and server.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Simple Block Physics Fabric | Fabric | 1.21.11 – 26.2 | Client or server, optional | 2026-08-22 |
| Cave-Instability | Fabric | 1.21.1 | Client and server | 2026-08-08 |
| PhysEx (Water Physics Overhaul) | Fabric and Forge | 1.16.5 – 1.21.11 | Client and server | 2026-08-17 |
| Collapsing Caves | Fabric, Forge and NeoForge | 1.20.1 – 26.3 | Client and server | 2026-09-22 |
Questions
Does Simple Block Physics Fabric need Fabric API?
Does the server need the mod for vanilla clients to join?
Which game versions have files?
In the catalog
Simple Block Physics Fabric is one of 19,031 Adventure mods on ModsFinder, and one of 10,052 Adventure mods for Fabric. 13,894 mods support Minecraft 26.2.
Similar mods
What the author says
This is a port of the original Simple Block Physics mod for Fabric and for newer versions of the game. This mod implements configurable, recursive structural instability. Utilizes a functional recursive search to assess block support upon adjacent removal, avoiding chunk scans.
Official listing
- Modrinth page
- modrinth.com/mod/simple-block-physics-fabric
- Owner
- jake404notfound
- Published
- 2026-02-22
- Updated on Modrinth
- 2026-08-22
- Facts verified
- 2026-10-15