Explore fire and smoke

Inferno Chamber has been removed from the official gallery. This page is retained as a reference for the internal performance fixture, not an available Atlas simulation.

The fixture contains 460,800 gas cells in a 96 × 80 × 60 volume above a 7,680-cell hearth: 468,480 cells in total. Apparently empty space is simulated air, including oxygen and velocity. Three fuel beds feed merging warm plumes; seeded smoke makes the volume visible on opening. Subsequent motion comes from the solver.

Inspect a step

Open the project in Studio and start with Step. This is a CPU stress scene; expect a long tick rather than interactive playback. A target of one step per second cannot force an expensive step to finish in that time. Camera and slices can still inspect the previous accepted frame while computation runs.

Use Slice or Split on X, Y or Z to expose the interior. Select a cell to inspect temperature, smoke, oxygen and velocity. Compare a fuel bed, the warm plume and surrounding cool air across a few recorded frames. Recompile to rebuild the project’s starting world.

Model and limits

The source uses normalized lattice units, not calibrated metres, seconds or kelvin. Fuel consumes oxygen and releases heat and soot. Heat drives upward acceleration; soot adds a small downward contribution. Six-neighbor viscosity and a discrete divergence calculation feed four pressure-relaxation passes and a velocity projection. First-order upwind transport carries heat, smoke, oxygen and velocity. Cooling and soot decay gradually dissipate the plume. The axis velocity cap of 0.28 keeps the summed transport coefficient below one.

These choices provide a readable approximate fluid experiment. Four pressure passes do not ensure incompressibility; each phase reads a consistent snapshot, and first-order advection loses fine detail. Boundary fallbacks model an open ambient reservoir, not a sealed room. There is no calibrated combustion chemistry, radiative heat transfer, subgrid turbulence or physically accurate light scattering. The voxel renderer colors hot gas orange/yellow and cool soot gray with transparency. Matching transparent neighbors merge into surfaces, so this is surface compositing rather than density integration through each gas cell. The starting opacity is tuned for that renderer.

Timeline and saving

Large worlds and bakes can consume substantial memory and storage. Source saves retain the starting recipe; a downloaded bake retains the recorded states. Use a state fork when a simulated frame should become a new project’s starting world. This fixture exceeds the browser preview recorder’s 50,000-cell budget. Atlas does not execute the heavy scene just to display a card. See bakes for local playback and the 512 MiB timeline limit.