fluidSim

A grid-based fluid solver running entirely on the compute substrate.

fluid.module is the API: create a simulation over a world-space box, add sources and forces, and step it. The five .computeShader assets beside it are the solver — advection, emitter injection, divergence, a Jacobi pressure solve, and projection.

The density field is a 3D texture, so volumetric rendering consumes it directly with no read-back.

local fluid = require("@builtin::systems.fluidSim.fluid")

local sim = fluid.create({
    resolution = { 64, 64, 64 },
    bounds = { min = { -2, 0, -2 }, max = { 2, 4, 2 } },
})

-- Each step, emit and advance.
sim:addSource({ position = { 0, 0.4, 0 }, radius = 0.08, density = 4, temperature = 30 })
sim:step(dt)

Emitters last one step, so a continuous plume re-adds its source each frame — which is also what lets emission follow a moving object.