Houdini Pyro — Fire and Smoke (beginner guide)

Run a sparse pyro simulation from source to cache. Here’s how to do it in Houdini on macOS, step by step — part of the free Houdini beginner curriculum.

Lesson 3 of the Houdini curriculum. Next up: FLIP Fluids.

What you’ll do

• Build a source: a Sphere SOP into a Pyro Source SOP, which emits density/temperature/fuel attributes onto points
• Drop a DOP Network node in the /obj context (or open the FX desktop’s Pyro shelf and use the “Explosion” or “Smoke” shelf tool for an auto-built network)
• Inside the DOP network, recognize the trio: Smoke Object (the simulation domain), Volume Source (brings in the SOP geometry as fields), Pyro Solver (Sparse) (the actual solver)
• Set the simulation frame range in the playbar AND verify substeps in the Pyro Solver Advanced tab — these are separate
• Adjust the shape operators (dissipation, disturbance, shredding, turbulence) on the Pyro Solver to art-direct the look
• Set Clamp Below to a sensible value (around 0.005 for density) to keep the sparse active region tight
• Cache the simulation: add a File Cache SOP downstream of the DOP Import and write VDBs to $HIP/cache/pyro/v001/
• Confirm the cache loaded by toggling the File Cache to Read From Disk and scrubbing — sim should play back instantly

Do it hands-free with Skilly

Reading steps is one thing; doing them while the menus are in front of you is another. Skilly is a voice-first tutor for macOS: you ask out loud — “where’s the pyro panel?” — and it answers while moving your cursor to the exact button, watching your actual Houdini window. It’s the same Houdini curriculum these lessons come from, taught live instead of read. Free to start.

Keep going

This is one stage of the full Houdini beginner curriculum. Continue with FLIP Fluids.