Houdini 18.5 Shelf tools Vellum tab

Vellum Cloth shelf tool

Configures vellum cloth from geometry and adds to current vellum simulation.

On this page

This tool lets you pick a piece of geometry and configure it as vellum cloth. It will then be added to the active simulation and merged with any other existing vellum objects.

Vellum cloth consists of a surface that doesn’t stretch or shear, but is able to bend with some amount of bend stiffness.


The internal collision and solve representation is always triangles, so quadrilateral meshes are implicitly triangulated. This can lead to what look like collisions when the triangulation for the render differs from the one used for the solve.

Using Vellum Cloth

  1. Select the geometry object to configure as vellum cloth.

  2. Click the Vellum Cloth tool on the Vellum tab.


There is a Surface Collider tool on the Vellum shelf that you can use for objects that will be colliding with your cloth. It is essentially the same as the Deforming Object shelf tool on the Collisions tab, as they are both designed for deforming objects. However the Surface Collider does not try to generate a VDB collision object, which is less expensive.

For specific parameter information, see the Vellum Constraints and Vellum Solver help.

Working with Vellum Cloth

  • One of the first things you may want to tweak is the Thickness parameter on the Vellum Constraints node. It’s important that the cloth is the right thickness for the effect you're trying to achieve.

  • Another commonly changed parameter is the Stiffness parameter on the Vellum Constraints node. This determines how bendy the cloth will be.

  • The Stretch and Bend Damping Ratios are two parameters that are set low by default. You can try bumping these up by factors of 5 to make your cloth look slightly less rubbery.

  • The Constraint Iterations default value of 100 is pretty good for most mid-resolution cloth on the Vellum Solver. However if you have high resolution cloth you may have to increase that value to 200 or even 500. The general rule is to use the number of points across the diameter of the cloth.

  • The Layer Shock parameter on the Vellum Solver controls how much lighter to make each layer of cloth when you have multiple layers. The default is to make the bottom layer 4 times heavier than the top layer. The layer attribute can be set with the Layer parameter on the Vellum Constraints node.

Vellum tab