Houdini 18.0 Reference

Houdini Engine Debugger

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Houdini Engine Debugger is a debugging server for applications which use the Houdini Engine. Houdini Engine allows Houdini technology to be integrated into any application. It is an API that allows Houdini digital assets to be used directly inside of the host application.


The debugger window can be summoned with Windows ▸ Houdini Engine Debugger. The window can be closed when the debugger is running.

Once the debugger is started a client application can be configured to connect to the running Houdini instance to execute HAPI calls. Those calls will execute in the context of the Houdini instance so the results can be seen immediately and inspected like a normal Houdini scene. The primary use of the debugger is to ease development of HAPI applications / plug-ins and digital assets used by the same.

The SideFX Unreal, Unity and Maya Houdini Engine plug-ins have a Session Type parameter which can be set to the host & port the debugger is running on.



User interface

  • Menus

    Explains each of the items in the main menus.

  • Viewers

    Viewer pane types.

  • Panes

    Documents the options in various panes.

  • Windows

    Documents the options in various user interface windows.


  • Expression functions

    Expression functions let you compute the value of parameters.

  • Expression cookbook

    Tips and tricks for writing expressions to accomplish various effects.

  • Python Scripting

    How to script Houdini using Python and the Houdini Object Model.

  • VEX

    VEX is a high-performance expression language used in many places in Houdini, such as writing shaders.

  • HScript commands

    HScript is Houdini’s legacy scripting language.

Command line

Guru level

Plugin installation

  • Houdini Packages

    How to write and combine multiple environment variable definition files for different plug-ins, tools, and add-ons.

Houdini Engine