Houdini Hair Simulation: 1M Strands with 200 Guides — HHS2:E4

1,000,000 hair strands in a simulation? Sounds insane, right? But here’s the trick—you don’t actually simulate every strand.

In this episode, we’re tackling Houdini’s powerful hair system and breaking down how to control thousands of hairs efficiently using guide curves. If you’ve ever wondered:

What are hair guides, and why do we use them?
Is simulating thousands of strands even practical?
How do we approximate hair motion at a fraction of the sim time?

Then this tutorial is for you! This effect got an overwhelming response on IG, so I’m breaking it down step by step! 💡

What You’ll Learn:
✅ The role of guide curves in Houdini’s hair system
✅ How to simulate a fraction of the hair count while keeping realistic motion
✅ Blending guide and render hairs for efficient, high-quality results

Important Topics:
🔹 Creating and understanding dynamic constraints on each simulation frame
🔹 Combining multiple Vellum Packed objects
🔹 Controlling Bend Stiffness using curveu attribute
🔹 Creating water droplets with soft body dynamics that sit and roll naturally on the hair
🔹 Shading and rendering hair using Redshift Principled Hair material and custom attributes

This setup is simple yet powerful, with real-world applications in animation, VFX, and motion design!

🔥 Want the working file? Head to my Instagram post by 21 Februrary 2025 and comment "GOOD HAIR DAY" to get the annotated Houdini file for this setup.

Instructor: Ronald Fong
Editor: Jasmine Seo

🔗 Full tutorial:    • Houdini Hair Simulation: 1M Strands with 2...  
💬 Have questions? Drop them in the comments!