Houdini 17.5 Shelf tools

Volume Light shelf tool

Simulates illumination from an emissive volume.

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Like the Geometry Light tool, this tool:

  1. Creates a Light object.

  2. Sets the Light type parameter to Geometry.

  3. Sets the Geometry object to the object you select.

This tool also:

  • Copies the volume’s shader into the new light’s Material parameter. This ensures that changes to the volume’s colors also affect the light.

  • Enables generation of a point cloud (stored in temporary memory using the temp: file prefix). Point clouds often speed up lighting from highly variable volume sources such as volumetric fire. To render the volume light without generating the point cloud, just turn off Light ▸ Area light options ▸ Enable point cloud.

Unlike the Geometry Light, creating a volume light does not turn off the display flag for the original geometry. The original volume is left in the scene so that it still shows up in the render.

Use the light object’s attenuation and spot light parameters to adjust the volume lighting if the physically correct defaults aren’t what you want.

How to

  1. Select the volume geometry you want to emit light.

  2. On the Lights and Cameras shelf tab, click the Volume Light tool.

This creates a new Light object and sets it up to emit light based on the volume.

Technical details

The volume light takes over the emission (Ce) component, which is treated as direct lighting for the new light source - making it possible to separate it into a distinct per-light deep raster plane separate from the combined direct_emission and indirect_emission planes.

Emission is disabled on the original object for all secondary rays (such as reflections) by disabling the Emission illuminates objects property on the source object. This ensures only the new light object directly illuminates other objects. (This property is on the Shading tab of the source object if you want to re-enable it.)

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.

  • Vellum tab

    The Vellum tab contains tools for creating different types of vellum effects.

  • 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.

  • 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.