Houdini Global Variables

Handy Houdini Global Variables

Here are some handy Houdini global variables that are commonly used in parameter expressions. This is for people just starting out with Houdini since I don’t think they will get past the second tutorial without seeing a global variable being used. Make sure you check the Houdini docs for a full listing.

Cheat Sheet

I talked about creating custom global variables in Houdini in a prior #QuickTip. Houdini, however, already has some predefined for you. One global variable that is especially useful and actually required to render out image sequences is the $F variable. You use the $F in rendered picture filename numbering e.g. $HIP/my_cool_image.$F.exr or when you are animating noise or passing it to a sin() or cos() function if you want to animate a cob of corn oscillating back and forth. Yet another one is $HIPNAME which gives you the name of the scene file without the extension. You can do some fancy naming of renders with this one.

I’ve included a pdf file for your enjoyment. Have fun!


Houdini HScript Global Variables pdf


I am a motion designer & developer based out of South Florida. When not designing or animating pixels, I wrangle some code. If all else fails, I watch Twilight Zone, I Love Lucy, or Three's Company reruns.