Base Matter

Base Matter is a fully 3D material simulation sandbox built around experimentation, machinery, and interacting systems.
Build structures, machines, pressure vessels, fluid systems, reactors, and whatever else you can come up with using a volumetric grid of simulated materials. Then start the simulation and see what happens.
Sand falls and piles up. Liquids flow and separate. Heat spreads through materials. Water freezes, boils, and condenses. Fuel needs oxygen to burn. Pressure builds inside sealed spaces and can rupture weaker materials. Salt dissolves into water. Plants consume resources and grow. Acid corrodes. Gunpowder chains. Machinery moves matter around the world.
Base Matter is designed as an open-ended sandbox. There are no missions, progression systems, or prescribed objectives. Build an experiment, run it, inspect the results, change something, and try again.
Build functional systems
Use pumps, valves, heaters, coolers, filters, fans, gas pumps, pistons, pushers, timers, sensors, switches, logic gates, sources, drains, and other devices to create working machines and automated experiments.
Recent builds also include basic nuclear reactor materials, including uranium, neutrons, control rods, copper heat conductors, and reactor steel.
Look inside your experiments
Base Matter is not just about watching things happen from the outside.
Switch between normal 3D editing, thin slice editing, and cutaway views to work inside complex builds. Use matter, heat, pressure, and power display modes to understand what the simulation is doing, and place probes to track values over time.
Experiment without losing your work
Pause the simulation, advance one tick at a time, save worlds, copy machines as reusable stamps, create checkpoints, and use limited rewind history to inspect or recover experiments.
Current features
Fully 3D voxel-based material simulation

Powders, liquids, gases, solids, fire, steam, molten materials, and more

Heat transfer and phase changes

Combustion and oxygen-dependent burning

Pressure and sealed chambers

Corrosion, explosions, growth, moisture, salinity, and material storage

Electrical logic and automation

Pumps, valves, filters, pistons, fans, heaters, coolers, and other machinery

Nuclear reactor materials

Slice editing and cutaway viewing

Heat, pressure, power, and matter visualization

Probes and graph history

Saves, autosaves, stamps, checkpoints, undo, and rewind

Built-in example scenes

Large worlds supporting roughly one million available cells

Early alpha
Base Matter is currently in active development. Systems may change, bugs are expected, and performance can vary significantly depending on world size and how much of the simulation is active.
The simulation is intentionally simplified and is designed for experimentation rather than scientific or engineering analysis.
If you build something interesting, strange, useful, or catastrophic, I want to see it.
Build it. Run it. See what happens.