Flow

Flow is a GPU-accelerated 3D fluid solver that simulates gaseous fluids using a 3D texture-based approach. This operator creates smoke, fire, and atmospheric effects by solving the Navier-Stokes equations for incompressible flow on the GPU. The simulation operates in a volumetric grid where velocity and substance density are stored as 3D textures, allowing for real-time interactive fluid dynamics.

The solver supports substance injection from POP point sources, volumetric source inputs, and various forces including buoyancy, gravity, external force fields, and optical flow. You can control fluid behavior through viscosity (thickness), vorticity (swirling motion), pressure iterations (incompressibility accuracy), and dissipation rates for both velocity and substance density. The simulation maintains mass conservation through a pressure projection step and supports collision boundaries and obstacles defined via 3D textures.

Flow optionally generates particle systems that are advected by the fluid velocity field, creating wispy smoke trails or fire ember effects. Particles can spawn from density regions and inherit color from the substance field with customizable lifespans and variance. The simulation outputs velocity, substance density, and temperature as 3D textures suitable for volume rendering or further processing, making it ideal for smoke plumes, fire effects, atmospheric disturbances, and abstract fluid art.