09 — Particle fluid

This case reads fixed-count fluid particles before and after 60 explicit physics steps and decodes the binary payload without NumPy.

Verification level

Visible native Isaac Particle Fluid. Acceptance requires real particle state, stable particle count, a later simulation tick, and the visible fluid moving under physics. The client uses only standard-library struct for decoding.

Run it

Terminal A, with a working GPU and display:

bash

cd demo/server/09_particle_fluid
fastsim config validate run.yaml --json
fastsim-server run.yaml

Terminal B:

bash

cd demo/server/09_particle_fluid
python main.py --timeout 60

The media type is application/vnd.fastsim.particle-fluid-f64. Headers state Run ID, exact entity ID, particle count, generation, tick/time, shape, little-endian float64 dtype, and layout. The body stores all position XYZ triples first, followed by all velocity XYZ triples. main.py verifies both payloads belong to the current Run and fluids.water, validates the exact byte count, and computes the position centroid before and after stepping.

Particle count is fixed for this API version. A backend without the advertised fluid query capability returns a typed unavailable error instead of fabricated data.

Next: 10 — Terminal close and remote security.