Houdini 16.5 Shelf tools

Expand from Objects shelf tool

Creates a force that pushes away from the selected object. This lets you expand (blow up) a fluid system at a specific time in a specific shape, which is useful for explosions.

On this page

(Technically, the expansive force is a divergence field.)

See fluid sourcing for information on how the tool transforms the input object into a source for the effect.

Using Expand from Objects

To...Do this

Create a fluid container

See Smoke Container, Flamefront Container, and Liquid Container.

Fill a fluid container

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

Create an expansion force

  1. Select the object you want to turn into an expansion field.

  2. On the Populate containers tab, click the Expand from Objects tool.

  3. Select the fluid container you want to expand in and press Enter.

Control the amount of expansion

In the DOP network, find the Source Volume node importing the divergence field (named source_divergence_from_object).

Use the Scale source volume parameter to control the amount of expansion. You can keyframe this value to delay and/or limit the expansion time, pulse the expansion, etc.

Sometimes very high values may be necessary (100+) to have visible effects.


  • The shelf tool adds a Fluid Source surface node to the object to convert its geometry into an appropriate volume, then imports the volume into the DOP network using a Source Volume node.

  • Most "populate containers" defaults are configured for a sphere with a radius of 1 unit. For much smaller or larger volumes, you may need to change settings on the Fluid Source surface node created by the shelf tool. The Sample Radius, Edge Location and Feather Length parameters give extensive control over how everything is sampled into a volume.

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.

Shelf tabs

  • Create tab

    Tools on the Create tab let you create and place primitives, curves, and null objects in the scene view.

  • Modify tab

    Tools on the Modify tab let you easily customize objects in the scene view.

  • Model tab

    Tools on the Model tab let you edit objects in the scene view.

  • Polygon tab

    Tools on the Polygon tab let you modify polygons in the scene view.

  • Deform tab

    Tools on the Deform tab let you deform objects in the scene view.

  • Texture tab

    Tools on the Texture tab let you texture objects in the scene view.

  • Rigging tab

    The Rigging tab contains tools for creating premade rigs.

  • Muscles tab

    The Muscles tab contains tools for creating muscles.

  • Characters tab

    Tools on the Character tab let you create characters in the scene view.

  • Constraints tab

    Tools on the Constraints tab create a constraint network where you can constrain objects to each other in the scene view.

  • Hair Utils tab

    Tools on the Hair Utils tab let you quickly set up hair and fur on objects.

  • Guide Process tab

    Tools on the Guide Process tab let you influence the placement and orientation of guide hairs by painting skin attributes.

  • Guide Brushes tab

    Tools on the Grooming tab let you add and directly manipulate hair.

  • Terrain FX shelf tab

  • Cloud FX tab

    The Cloud FX tab contains tools for creating cloud effects.

  • Volume tab

    The Volume tab contains tools for creating volume effects.

  • Lights and Cameras tab

    Tools on the Lights and Cameras tab let you create and place lights and cameras in the scene view.

  • Collisions tab

    Tools on the Collisions tab let you create collision objects in the scene view.

  • Particles tab

    Tools on the Particles tab let you create dynamic particle simulations.

  • Grains tab

    The Grains tab contains tools for simulate grains of sand and other granular matter.

  • Rigid Bodies tab

    Tools on the Rigid Bodies tab let you create dynamic RBD objects in the scene view.

  • Particle Fluids tab

    Tools on the Particle Fluids tab let you create particle based liquids in the scene view.

  • Viscous Fluids tab

    Viscous fluids are FLIP simulations that use a temperature attribute to drive viscosity.

  • Oceans tab

    The Oceans tab contains tools for creating ocean simulations.

  • Fluid Containers tab

    The Fluid Containers tab contains tools for creating pyro, smoke, and liquid containers.

  • Populate Containers tab

    The Populate Containers tab contains tools for creating and removing fire, smoke, and liquid.

  • Container Tools tab

    The Container Tools tab contains tools for manipulating fire, smoke, and liquid.

  • Pyro FX tab

    Tools on the Pryo FX tab let you create simulated smoke and fire effects.

  • Cloth tab

    Tools on the Cloth tab let you create and constrain cloth objects in the scene view.

  • Solid tab

    Tools on the Solid tab let you create and modify solid objects.

  • Wires tab

    Tools on the Wires tab let you create flexible dynamic objects in the scene view.

  • Crowds tab

    The Crowds tab contains tools for creating crowds, crowd behaviors, as well as examples.

  • Drive Simulation tab

    Tools on the Drive Simulation tab let you manipulate dynamic objects in the scene view.