Harlow documentation
Project Harlow adds a real-time GPU path tracer and a set of GPU solvers to TouchDesigner. Liquids, smoke and fire, rigid and soft bodies, fracture and surface weathering are simulated on the GPU and rendered with physically based lighting, all driven by ordinary POPs.
Each chapter covers one operator and opens with the TouchDesigner operator it replaces or works beside, a Quick start for a first result in a few steps, and a table of the attributes it reads and the parameters it exposes. Advanced sections at the end of each chapter cover internals, performance and limits.
Start here
The operators, how they connect, and how the solvers couple.
Requirements, where the files go, and getting a license key.
POPs, attributes, path tracing and how parameters are named.
Operators
Materials and maps for the path tracer. Replaces the Geometry COMP.
OptiX, ReSTIR and DLSS-RR rendering. Replaces the Render TOP.
FLIP liquid as a surface mesh or particles.
Spray, foam and bubbles from a Liquid POP.
Smoke, fire and explosions on a 3D grid.
Rigid and soft bodies, joints, chains and dents.
Voronoi prefracture into solid pieces for Bodies.
Surfaces that get wet, burn, char and melt.
Simulations in a mesh's UV space, stitched across seams.
Reference
Every material preset by number.
Counters and timings each operator reports.
What each Harlow operator replaces or works beside.
Symptoms, causes and fixes.
Need a key? Patrons get one from the license page. Stuck? See Troubleshooting, the FAQ or get in touch.