Blender hair simulationOptiX + CUDA
XPBD
Hair
Particle-chain XPBD hair with predictive BGRP contact that constrains a candidate before it crosses the contact shell.
Collision before acceptance.
Each Curves point becomes a particle. XPBD stretch preserves adjacent lengths, while three-point bend constraints preserve the rest chord. BGRP samples every active segment along its axis and provides a stable surface feature, outward normal, and signed separation.
Start-surface predictive contact and end-feature re-query are alternated with stretch and bend. The solver removes only inward relative normal velocity, preserving sliding and friction.
Highlights
Predictive contactConstrain the unaccepted candidate before it can cross the shell.
Coupled repairStretch, bend, and contact reconverge together after re-query.
RT Core searchBGRP delegates deforming triangle traversal to OptiX.
Direct outputAccepted particle positions become the Curves result without rod reconstruction.
Inspect the predictive solver.
Source, specification, and validation cases are published together.