Houdini 19.5 Shelf tools

Melt Object shelf tool

Creates a melting object from geometry.

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This tool turns a geometry object into a particle fluid with a temperature attribute that affects the viscosity of the object. You would typically want to use this tool whenever you have an object that will change state over time. For example, you could use this tool to create a warm chocolate bunny that would slump over and then cool off and become solid.


You will often want to use this tool in conjunction with the Heat Within Object shelf tool, which would allow you to have an object that melts when it comes in contact with the temperature generated from another object.


The difference between this tool and Lava From Object is that this tool doesn’t apply any shader. The Lava From Object assigns a shader to get a basic glowing lava look.

Using Melt Object

  1. Create a geometry object to be converted into a melting object.

  2. Click the Melt Object tool on the Viscous Fluids tab.

    For specific parameter information, see the FLIP Object and Gas Temperature Update help pages.


To...Do this

Change how quickly the objects starts to melt

Modify the Temperature parameter on the Physical tab of the FLIP Object. This parameter sets the initial temperature of the object. The default value is 0.5, which will cause it to melt immediately, since the object starts off quite warm. A higher value will give you very hot, free-flowing liquid which cools over time and a lower value would give you cool, highly viscous fluid that heats up and melts.

Change the look of the fluid

Adjust the Minimum/Maximum Viscosity parameters on the Gas Temperature Update node. A value of 100,000 is very stiff, which should retain it’s shape, and a value of 0 is completely liquid, like water.

Control how quickly a hot temperature will cool off

Modify the Outer/Inner Cooling Rate parameters on the Gas Temperature Update node. The Outer Cooling Rate refers to the rate of change on the surface of the object, while the Inner Cooling Rate refers to how fast the temperature changes inside the fluid. Generally, the inner cooling should be lower than the outer, since the inside of the object is insulated and retains more heat, as opposed to the exterior which loses heat more quickly due to the surrounding air.

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.