Tumble brings physical objects to Minecraft. It is a Fabric mod built around Box3D, with a focus on multiplayer and familiar Minecraft behavior.
Tumble is in early development. You can turn blocks into props and move them with the tools in the creative inventory. Multiplayer, saving and performance are still being tested. See what's left before using it in a world you care about.
The Gravity Gun, Physics Gun and Tool Gun are creative and developer tools. They have no default survival recipes or progression. Find them in the Tumble creative tab or use the operator commands /tumble gravitygun, /tumble physicsgun and /tumble toolgun. A server can add recipes through an optional datapack.
Physics runs on the CPU using Box3D. Minecraft uses the GPU for rendering; Tumble does not currently run its physics on the GPU.
Development JARs are available from Jenkins. Releases will be published on GitHub Releases. You'll need Minecraft 26.3, Fabric Loader, Fabric API and Fabric Language Kotlin.
Use JDK 25, then run:
./gradlew clean build -PacceptMinecraftEula=trueThis builds the mod and runs the physics tests and server GameTests. Run ./gradlew runClientGameTest -PacceptMinecraftEula=true for the client tests, and ./gradlew runProductionGameTest -PacceptMinecraftEula=true to test the packaged JAR with a Fabric server. The flag accepts the Minecraft EULA for the test server. The finished JAR is in build/libs/.
The build targets Minecraft 26.3. Later snapshots are not supported yet.
Contributions are welcome, including work made with coding agents. See CONTRIBUTING.md for the build, testing and pull request guidelines.
Making a server-side addon? Start with the addon API guide.
Tumble is licensed under MPL 2.0. Box3D4j and the libraries it bundles keep their own licenses.