When you want to share a quick preview of your animation in Houdini, it’s better to export a playblast (recording of the viewport), rather than wait for a lengthy render.
A step by step explanation follows:
Here I choose JPEG format, because I don’t care about quality when it comes to playblast. Downscaling resolution can help maintain the resulting GIF size small.
This creates JPEG frames in the folder where your Houdini file resides. Now to join them into video or GIF, you can use your favourite video editor, or simply use command-line tool called ffmpeg. Open a command line in a folder where you have your frames and run the command:
ffmpeg -i my_preview%d.jpg -filter_complex "[0:v] split [a][b];[a] palettegen [p];[b][p] paletteuse" out2.gif