Houdini Velocity Forces 2: Advanced

January 20th 2024 03:40:20pm

“Velocity Forces 2.0: Advanced” is an in-depth class expanding on Velocity Forces 1.0. It delves deeper into creating velocity fields, exploring the differences between Houdini Standard Volumes and OpenVDB volumes.

The course focuses on techniques to help you refine velocity fields, blend multiple fields together, and use alternative simulation outputs for unique movement. You’ll learn how to create vorticles, enhance simulations with wake turbulence forces, as well as injecting extra detailed motion into low-resolution smoke sims. Additionally, this class will cover volume optical flow fields on both 2D planar and 3D geometry, plus utilizing the Potential Flow node for 3D surface advection.

This class will also show how to move beyond volume-based fields into dynamic VEX coding, reducing the volume caching overhead, while also tackling advanced mathematical concepts, from matrices and quaternions to cross products and vector math.

Session 1
Volumes, Volumes, Volumes!

Dive into a better understanding of the volumetric formats available, their pros and cons, how to make them from scratch, masking them, blending them, and generating them from sim data.

  • Volumes Illustrated
    • Houdini Standard Volumes
    • OpenVDB volumes
    • VDB Tree Structure
  • References
    • density field
    • vel field
  • Field Masking
    • Add, Subtract, Multiply
    • Dealing with “Jaggies” / Stepping
  • Velocity Fields From Sim Data
  • Cloth driven POPs
  • Pyro driven Threads
  • Session 2
    Round and round we go!

    Blend two distinctly unique vel fields to generate a single vel field, and explore how to build and implement vorticle influence into your sims.

  • Field Blending
    • Blend various VEX/VOP fields
  • Vorticles
    • Intro, and references
    • POP static
      • Concepts
      • Orientation vectors
    • POP randomized orientation
      • Seed generation
      • Extracting vectors from orientation
    • POP randomized continuous rotation
      • Defining stable seed rotations
    • POP randomized translation
      • Seed orientation on surface while moving
    • Sim Examples
      • RBD Wooden fencing
      • FLIP Muddy swirls
      • Vellum shredded cloth
      • Vellum hair blown
      • Pyro Wake Turbulence
    • Gas Vorticle Forces node

    Session 3
    Stay close!

    Wield Optical Flow data into driving surface movement, and learn how to generate and confine motion to surfaces. Also see how it’s possible to deform volumetrics post sim.

  • Optical Flow
    • Concepts
    • Volume Optical Flow 2D planar & 3D surfaces
    • Sim Examples
      • FLIP water
      • Vellum grains
      • Vellum cloth
      • Pyro smoke
  • Surface Flows
    • Intro
    • VDB Potential Flow node
    • Gradient fields
    • Extracting vel from color
  • Post Pyro Deformation
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