Houdini FLIP Fluids (beginner guide)

Simulate water, splashes, and viscous fluids with the FLIP Solver 2.0. Here’s how to do it in Houdini on macOS, step by step — part of the free Houdini beginner curriculum.

Lesson 4 of the Houdini curriculum. Next up: RBD Destruction with Bullet.

What you’ll do

• Source fluid from geometry: a closed mesh into a FLIP Source SOP (or use the “FLIP Tank” or “Fill Object” shelf tool for an auto-built setup)
• Inside the DOP network, recognize: FLIP Object (particle container), FLIP Solver 2.0 (the solver), Static Object / RBD Object as colliders
• Understand particle separation — the spacing between particles. Smaller = more detail = exponentially slower. Start coarse (0.1), refine later
• Confirm reseeding is enabled on the FLIP Solver — it maintains particle density as the fluid stretches and compresses
• Set substeps on the FLIP Solver for fast motion (2-4 typical, more for splashes)
• Cache the particle simulation to BGEO sequence with File Cache SOP
• Mesh the cached particles using Particle Fluid Surface SOP — set Particle Separation to match the sim, Influence Scale around 2-3, Voxel Scale 1.0
• Alternative meshing chain: VDB From Particles → VDB Smooth (5-10 iterations) → Convert VDB to polygons for greater control
• Cache the meshed result separately from the particle sim — meshing is expensive and should not re-run on every render

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 flip 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 RBD Destruction with Bullet.