JIGPX
JIGPX

RBD Example Setup

Basic rigid body dynamics setup in Houdini for destruction simulations

Overview

Rigid Body Dynamics (RBD) in Houdini provides a powerful system for creating realistic destruction and collision simulations. This example demonstrates a basic setup for fracturing objects and simulating their physical interactions.

Preview

Full resolution preview of the RBD simulation

Node Network Structure

Overview of the RBD network structure

Overview of the RBD network structure

Initial geometry setup and fracturing

Initial geometry setup and fracturing

RBD Solver configuration

RBD Solver configuration

Collision and dynamics settings

Collision and dynamics settings

Post-processing and output setup

Post-processing and output setup

Key Components:

  • Input Geometry: The object(s) to be fractured and simulated
  • RBD Material Fracture: Creates the broken pieces with interior detail
  • RBD Solver: Handles the physics simulation and collision detection
  • Ground Plane: Collision surface for the simulation
  • Output Processing: Post-simulation cleanup and attribute management

Common Parameters

Essential Settings:

# RBD Material Fracture
interior_detail = 1
fracture_pattern = voronoi
piece_count = 20

# RBD Solver Parameters
substeps = 2
collision_margin = 0.01
gravity = {0, -9.81, 0}
friction = 0.3
bounce = 0.3

# Attribute Wrangle for Glue Parameters
@strength = @maskglue*10;
@stiffness = @maskglue +.1;
@angularstiffness = @maskglue +.1;
@dampingratio = @maskglue *.1 +.1;
@angulardampingratio = @maskglue *.1 +.1;

Tips for Parameter Adjustment:

  • Increase substeps for more stable simulations
  • Adjust collision_margin based on object scale
  • Use friction and bounce to control object interaction
  • Modify piece_count for different fracture granularity

Best Practices

  • Use a File Cache SOP to save simulation results
  • Add constraints or glue to control fracture behavior
  • Consider using clustering for more natural break patterns
  • Add noise or custom patterns to fracture points
  • Use proper collision geometry for accurate interactions