Houdini 18.5 Shelf tools

Simple Fireball shelf tool

Creates a large rising and expanding explosion.

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Overview

This shelf tool sets up a sparse pyro simulation of a medium-size explosion. Rather than building a DOP network, it uses the SOP-level tools to build a simple network to work with sparse pyro.

The explosion consists of an initial blast, followed by a rising fireball. As long as there are sufficient reactants (corresponding to the emissive flame field), the fireball will continuously emit soot and heat and continue to expand. These various outputs, as well as the time it takes the fireball to burn up, are controlled through parameters on the Flames tab of the Pyro Solver.

Using Simple Fireball

  1. Click the Simple Fireball tool on the Simple FX tab.

  2. Select the location of the fireball in the viewport.

Understanding Simple Fireball

  • If you have a Houdini FX License, you can dive inside the solver and edit the subnet with custom DOP forces. Otherwise, you can stay at the SOP level and use the exposed parameters on the node.

  • create_burn sets up the temperature and burn sources. Burn gets merged with the pyro flame field (to refresh the available reactants) and the divergence field (causing the initial outward explosion). Rates of the sourced values are animated through the Scale parameters of the Pyro Source node.

  • The shape of the base is determined by the geometry of the starting node in the chain, which is a sphere by default.

  • The parameters on the Pyro Solver SOP have the greatest influence on the motion and emergent shape of the fireball and its smoke.

  • The Visualize buttons on the pyro solver let you toggle on and off visualizers for velocity, temperature, and flame.

  • If you dive inside the Pyro Bake Volume node, you can use the following controls on the Pyro Shader to do the following.

    To...Do this

    Change the color of the smoke based on density

    1. Change the menu next to Smoke Color from Constant to Use Ramp.

    2. Set the Density Range parameter to control the color of the smoke at given density values.

    3. Set the Smoke Color Ramp to change the color of the smoke based on Density Range.

    Change the color of the smoke based on how light scatters through the volume

    Change the Absorption Color. The value of 0.425 (red),0.36(green), 0.3(blue) could be a good starting point for more realistic looking smoke.

    Scale smoke density using an other volume

    1. Turn on the Use Control Volume checkbox.

    2. Set Density Control Volume on the Bindings tabs to the field that you want to use to affect the density. Usually temperature or flame are good choices for this purpose.

Note

You can download a fully configured, production ready version of this shelf tool from the SideFX Content Library.

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

  • Simple FX tab

    The Simple FX tab contains tools for creating dynamic simulations at the geometry level.

  • 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 Pyro FX tab let you create simulated smoke and fire effects.

  • Sparse Pyro FX tab

    Tools on the Sparse Pyro 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.

Technical