Inventory Physics
by TheKryzzz_
Inventory Physics replaces the static inventory grid with a two-dimensional physics simulation in which items fall, bounce and stack.
What it does
Main inventory slots 9 to 35 are simulated inside a physical chamber. Each item behaves as a rigid body, and collisions between items and the chamber walls are detected with the Separating Axis Theorem, using sub-stepping for accuracy. Items settle into stacks the way loose objects would in a box, and the whole effect runs on the client, so servers need nothing installed.
The simulation gives each item type its own physical parameters, including mass, friction, bounciness, air damping and collision behavior. Heavy blocks such as anvils, stone and netherite have higher mass and bounce less, slimeballs bounce higher, feathers drift down slowly because of their air damping, and ice slides with much reduced friction. Movement of the player, including jumping and falling, transfers inertia to the items inside the inventory. Items can also be picked up and tossed with drag interactions.
The mod is published for NeoForge only, and the 1.21.1 build is the only game version listed. Inventory Physics is released under All rights reserved and is not open source. The latest file is 0.7.6 for 1.21.1, dated 2026-09-04, after the first release on 2026-09-01.
Key features
Two-dimensional rigid bodies
Inventory slots become physical objects that collide, rest on one another and move according to simulated forces.
Material-specific properties
Each item type has its own mass, friction, bounciness and air damping, so heavy and light items behave differently.
Inertia from player movement
Jumping, falling and other vertical movement push the items inside the inventory, so they respond to the player's motion.
Interactive drag toss
Items can be dragged and tossed inside the simulated chamber, which lets the player move them by hand.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Playing with a physical inventory
A player who wants a livelier inventory screen can use the mod to watch items settle, bounce and pile up as they move.
Who it’s for: Players on NeoForge 1.21.1 who want a decorative or playful inventory. Because the environment is client-side only, multiplayer players install it alone, and server owners do not need to add anything.
Questions
Does Inventory Physics need to be installed on the server?
Which loader and version does Inventory Physics support?
In the catalog
Inventory Physics is one of 8,016 Management mods on ModsFinder, and one of 2,689 Management mods for NeoForge. 32,366 mods support Minecraft 1.21.1.
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What the author says
Inventory Physics is a client-side mod for Minecraft 1.21.1 (NeoForge) that replaces the standard static 3x9 storage slot grid in the player's inventory with a 2D physics chamber. Items inside behave as physical rigid bodies that fall, collide, bounce, and interact dynamically.
Official listing
- Modrinth page
- modrinth.com/mod/inventory-physics
- Owner
- TheKryzzz_
- Published
- 2026-09-01
- Updated on Modrinth
- 2026-09-04
- Facts verified
- 2026-10-15