Dynamic Falling Tree

Dynamic Falling Tree

Realistic tree falling physics for Minecraft 1.21.1 (Fabric). When you chop a tree, it falls over using rigid-body physics instead of instantly disappearing.

What It Does

• Chopping the base log of a tree causes the entire tree to tip over and fall using real physics simulation.
• Blocks are removed flicker-free via a BARRIER -> AIR sequence in the same server tick.
• Trees spawn impact smoke particles when they hit the ground.
• Leaves break naturally after the tree settles, with vanilla particle effects.
• Works on rootless/floating trees as well as grounded ones.

Requirements

| Dependency | Version |
| ——————————————- | —————– |
| Minecraft | 1.21.1 |
| Fabric Loader | >= 0.16.9 |
| Fabric API | >= 0.110.0+1.21.1 |
| Sable | >= 1.2.2 |

Installation

1. Install Fabric Loader for 1.21.1.
2. Download Sable and place it in your mods/ folder.
3. Download this mod’s JAR and place it in mods/.
4. Launch and chop a tree.

Configuration

Config file auto-generates at .minecraft/config/treephysics.properties:

rootless_tree_detection=true
requires_axe=false
prevent_interacting_with_trees=true
rooted_dirt_generation=true
impulse_torque=2.0
impulse_force=1.5

| Option | Description | Default |
| ——————————– | ————————————————— | ——- |
| rootless_tree_detection | Allow floating trees to fall. | true |
| requires_axe | Only trigger physics when holding an axe. | false |
| prevent_interacting_with_trees | Block placing/using items on falling trees. | true |
| rooted_dirt_generation | Generate rooted dirt under naturally spawned trees. | true |
| impulse_torque | Rotational force applied to falling trees. | 2.0 |
| impulse_force | Linear push force applied to falling trees. | 1.5 |

How It Works

1. Detection: Breaking a log triggers a flood-fill search for connected logs, leaves, and attached blocks.
2. Validation: The detected structure is validated as a tree (must have a root on dirt or have leaves if rootless mode is on).
3. Assembly: Valid tree blocks are converted into a Sable ServerSubLevel — a physics-backed block container with independent collision and transform.
4. Flicker Fix: Original world blocks are replaced with BARRIER, then immediately AIR, preventing any visual flicker.
5. Impulse: A directional force and torque are applied based on the player’s position, causing the tree to tip over.
6. Impact & Decay: While falling, the server tracks velocity. Ground contact spawns smoke particles. After settling, leaves break naturally.

Technical Details

• Built on the Sable physics engine using SubLevel rigid-body simulation.
• All physics runs server-side and syncs to clients over the network.
• Singleplayer and multiplayer compatible.
• Licensed under MIT.