Stir a little color into science. Make a swirl. See what moves.
≋4 models · 13 experiments Switch freely. Each model keeps its state.
Pause freezes time. Reset restarts this experiment with your current controls.
LIVE SIMULATION
Objects & obstacles up to 6
Solid shapes redirect the fluid. Choose an object to resize or move it; overlaps form one solid. Shapes are clipped at the cube walls.
No objects yet. Add one or try “Flow around a sphere” below.
Move object tool: drag in its Z plane; arrows move X/Y, Page Up/Down moves Z. Pausing helps inspect the flow. Objects remain fixed while the fluid evolves.
THE FLUID IS YOUR CANVASColor traces where the fluid travels.
Drag to stir · Tap to add dye2D / 96 × 96
Dye is a tracer. Its color is not temperature or pressure.
FOLLOW YOUR CURIOSITY
Three little experiments.
Choose one. Change something. Watch.
Catch a current: follow the ribbons. Switch to Rotation to find the centers of spinning motion.
A LITTLE UNDERSTANDING GOES A LONG WAY
Why does it curl?
Different parts of the fluid move at different speeds and in different directions. Their local rotation is called vorticity. In Rotation view, coral and teal mark opposite spin directions.
What keeps it moving?
Your brush adds momentum. The flow carries that motion onward, while viscosity smooths velocity differences. Pressure is adjusted to keep the simulated fluid approximately incompressible.
A model, with boundaries.
This is a flat, enclosed tank with reflecting, free-slip walls. It models flow and dye, not waves, splashes, gravity, or a water surface. Colors fade slowly to keep the canvas readable.