How To Inflate A Mesh Like A Balloon In Houdini | Animation Inside Vellum Solver Node
Vellum Configure Balloon
This tool lets you pick a piece of geometry and configure it as vellum balloon. It will then be added to the active simulation and merged with any other existing vellum objects.
A balloon consists of two types of constraints. A stretchable cloth constraint is built for the outer surface. A pressure constraint is added to keep the cloth from collapsing. The pressure constraint uniformly pushes the cloth outwards to maintain a global volume, so squeezing one area will bulge distant areas.
This is more expensive than a Vellum Strut Softbody since instead of creating struts between opposite interior points, it computes the volume of the entire model and inflates or shrinks the model to keep the same volume. The Vellum Strut Softbody is a better choice for soft bodies as it is faster to solve.