Houdini 20.0 Shelf tools

Pump from Objects shelf tool

Gives smoke a velocity as soon it touches the pump.

On this page


This tool can be used to give smoke direction. The selected geometry is converted into a pump volume that defines the region of the pump’s influence, and a velocity volume, v. The velocity fields is obtained by rasterizing the v attribute of points scattered on the surface. Hence, the selected geometry must have the desired pump velocity stored in the v attribute.


You can use the Point Velocity SOP to add a v point attribute to geometry.


This tool only works with smoke and pyro simulations.

Using Pump from Objects

To...Do this

Create a fluid container

See Smoke Container or Pyro Container.

Fill a fluid container

See Source from Surface, Source from Points, and Source from Volume.

Create a pump

  1. Click the Pump from Objects tool.

  2. Select the object to generate the velocity and press Enter.

  3. Select the fluid container and press Enter.

Control the added velocity

In the DOP network, find the Volume Source node importing the pump field (named source_v_from_object).

Use the Scale parameter for the vel field to control the added velocity. You can keyframe this value to delay and/or limit the pump time, pulse the pump, etc.

In the example below, the sphere is a liquid source, and the box is a pump:

See also

Shelf tools

Using the shelf

  • Customize the shelf

    How to change the look of the shelf, change and rearrange its contents, and create your own shelf tools.