This R&D explores Houdini Vellum, introduced as a unified GPU/OpenCL-accelerated multi-solver for cloth, hair, soft bodies, and grains.

I started by testing the cloth workflow, and one of the first impressions was how much more artist-friendly and straightforward the setup felt compared with more traditional cloth simulation workflows.

For cloth specifically, Vellum uses an XPBD-inspired constraint-based solver, designed to provide stable and efficient simulation while keeping the setup relatively simple. It supports workflows such as multi-layer clothing, panel-based garments, draping, stitching, tearing, and other constraint-driven cloth behaviours.

One of Vellum’s biggest strengths is that it is a unified solver. Cloth, hair, grains, and soft bodies can all interact within the same simulation framework instead of being treated as completely separate systems.

This makes it especially useful for more complex character and CFX setups, where different material behaviours need to interact with each other in a consistent and controllable way.